Hi Vladimir,
I don’t think there is something like a incremental full text index for the moment [1]. As index is per collection, the recommanded way shall be to split your data in two collections :
- A big readonly collection of all the past updates, indexed once
- A small/medium sized collection whom full text index can be recreated in an acceptable time after each update. At the end of a predefined time period, you have to add the live collection to the readonly one, reindex it, and truncate the live one.
Best regards from France, Fabrice Etanchaud
[1] http://docs.basex.org/wiki/Indexes#Updates
De : BaseX-Talk [mailto:basex-talk-bounces@mailman.uni-konstanz.de] De la part de ???????? ???????? Envoyé : jeudi 21 juin 2018 16:02 À : BaseX Objet : [basex-talk] Full-Text
Hi, everyone!
Is there any way to index only imported xml-files? Now, when I import xml-files the full-text index is deleted. After importing I recreate whole full-text index and it takes too much time :(
-- С уважением, Ветошкин Владимир Владимирович
Hi Vladimir,
So what about storing those specific files in an ad-hoc collection, and only index that one ? Is there a partition pattern you could use to split these specific files in several collections of medium size ?
If you do not need fulltext capabilities, you can use incremental text() or attribute indices. Do you need to index only a specific set of text() or attributes ? If so, you can also specify a list of element or attribute names to be indexed, and by the way reduce the time needed to reindex.
Best regards, Fabrice
De : Ветошкин Владимир [mailto:en-trance@yandex.ru] Envoyé : lundi 25 juin 2018 09:42 À : Fabrice ETANCHAUD; BaseX Objet : Re: [basex-talk] Full-Text
Hi, Fabrice! Thank you.
All databases constantly change.That is why there is no way to single out "a big readonly collection" :( Maybe it is possible to use some other incremental indexes? I have to index specific xml-files, not all files in database.
21.06.2018, 17:16, "Fabrice ETANCHAUD" fetanchaud@pch.cerfrance.fr:
Hi Vladimir,
I don’t think there is something like a incremental full text index for the moment [1].
As index is per collection, the recommanded way shall be to split your data in two collections :
- A big readonly collection of all the past updates, indexed once
- A small/medium sized collection whom full text index can be recreated in an acceptable time after each update.
At the end of a predefined time period, you have to add the live collection to the readonly one, reindex it, and truncate the live one.
Best regards from France,
Fabrice Etanchaud
[1] http://docs.basex.org/wiki/Indexes#Updates
De : BaseX-Talk [mailto:basex-talk-bounces@mailman.uni-konstanz.demailto:basex-talk-bounces@mailman.uni-konstanz.de] De la part de ???????? ???????? Envoyé : jeudi 21 juin 2018 16:02 À : BaseX Objet : [basex-talk] Full-Text
Hi, everyone!
Is there any way to index only imported xml-files?
Now, when I import xml-files the full-text index is deleted.
After importing I recreate whole full-text index and it takes too much time :(
--
С уважением,
Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
Hey, Vladimir!
Just put this specific files to the separated DB and than index it.
You can process it automatically, BaseX allows to create and index DB right from XQuery.
I hope it helps you. Anyhow, you can provide more details about your task and we can figure out the best solution for you.
On Mon, Jun 25, 2018 at 10:42 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Fabrice! Thank you.
All databases constantly change.That is why there is no way to single out "a big readonly collection" :( Maybe it is possible to use some other incremental indexes? I have to index specific xml-files, not all files in database.
21.06.2018, 17:16, "Fabrice ETANCHAUD" fetanchaud@pch.cerfrance.fr:
Hi Vladimir,
I don’t think there is something like a incremental full text index for the moment [1].
As index is per collection, the recommanded way shall be to split your data in two collections :
A big readonly collection of all the past updates, indexed onceA small/medium sized collection whom full text index can berecreated in an acceptable time after each update.
At the end of a predefined time period, you have to add the live collection to the readonly one, reindex it, and truncate the live one.
Best regards from France,
Fabrice Etanchaud
[1] http://docs.basex.org/wiki/Indexes#Updates
*De :* BaseX-Talk [mailto:basex-talk-bounces@mailman.uni-konstanz.de] *De la part de* ???????? ???????? *Envoyé :* jeudi 21 juin 2018 16:02 *À :* BaseX *Objet :* [basex-talk] Full-Text
Hi, everyone!
Is there any way to index only imported xml-files?
Now, when I import xml-files the full-text index is deleted.
After importing I recreate whole full-text index and it takes too much time :(
--
С уважением,
Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
Hey Vladimir,
You can use sharding approach for you data import and split all DBs even every month.
On Mon, Jun 25, 2018 at 11:50 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Alexander! Thank you!
In my previous letter I have described the proccess in short. I'll think about separated DB. But I'm afraid that this base will also be very big in future. Although I can try to split data to several databases - one per year.. Hmm..
25.06.2018, 11:25, "Alexander Shpack" shadowkin@gmail.com:
Hey, Vladimir!
Just put this specific files to the separated DB and than index it. You can process it automatically, BaseX allows to create and index DB right from XQuery.
I hope it helps you. Anyhow, you can provide more details about your task and we can figure out the best solution for you.
On Mon, Jun 25, 2018 at 10:42 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Fabrice! Thank you.
All databases constantly change.That is why there is no way to single out "a big readonly collection" :( Maybe it is possible to use some other incremental indexes? I have to index specific xml-files, not all files in database.
21.06.2018, 17:16, "Fabrice ETANCHAUD" fetanchaud@pch.cerfrance.fr:
Hi Vladimir,
I don’t think there is something like a incremental full text index for the moment [1].
As index is per collection, the recommanded way shall be to split your data in two collections :
A big readonly collection of all the past updates, indexed onceA small/medium sized collection whom full text index can berecreated in an acceptable time after each update.
At the end of a predefined time period, you have to add the live collection to the readonly one, reindex it, and truncate the live one.
Best regards from France,
Fabrice Etanchaud
[1] http://docs.basex.org/wiki/Indexes#Updates
*De :* BaseX-Talk [mailto:basex-talk-bounces@mailman.uni-konstanz.de] *De la part de* ???????? ???????? *Envoyé :* jeudi 21 juin 2018 16:02 *À :* BaseX *Objet :* [basex-talk] Full-Text
Hi, everyone!
Is there any way to index only imported xml-files?
Now, when I import xml-files the full-text index is deleted.
After importing I recreate whole full-text index and it takes too much time :(
--
С уважением,
Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
-- s0rr0w
-- С уважением, Ветошкин Владимир Владимирович
Hi, Vladimir,
If you will do db names with the particular prefix, for example "db_", you may use the next code
let $docs := for $i in db:list()[starts-with(.,"db_")] return db:open($i) return $docs/*
On Mon, Jun 25, 2018 at 12:32 PM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Alexander,
Some questions: After that, how can I perform a search in all of these databases? Can I search for substring without fulltext using only text index?
25.06.2018, 11:56, "Alexander Shpack" shadowkin@gmail.com:
Hey Vladimir,
You can use sharding approach for you data import and split all DBs even every month.
On Mon, Jun 25, 2018 at 11:50 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Alexander! Thank you!
In my previous letter I have described the proccess in short. I'll think about separated DB. But I'm afraid that this base will also be very big in future. Although I can try to split data to several databases - one per year.. Hmm..
25.06.2018, 11:25, "Alexander Shpack" shadowkin@gmail.com:
Hey, Vladimir!
Just put this specific files to the separated DB and than index it. You can process it automatically, BaseX allows to create and index DB right from XQuery.
I hope it helps you. Anyhow, you can provide more details about your task and we can figure out the best solution for you.
On Mon, Jun 25, 2018 at 10:42 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Fabrice! Thank you.
All databases constantly change.That is why there is no way to single out "a big readonly collection" :( Maybe it is possible to use some other incremental indexes? I have to index specific xml-files, not all files in database.
21.06.2018, 17:16, "Fabrice ETANCHAUD" fetanchaud@pch.cerfrance.fr:
Hi Vladimir,
I don’t think there is something like a incremental full text index for the moment [1].
As index is per collection, the recommanded way shall be to split your data in two collections :
A big readonly collection of all the past updates, indexed onceA small/medium sized collection whom full text index can berecreated in an acceptable time after each update.
At the end of a predefined time period, you have to add the live collection to the readonly one, reindex it, and truncate the live one.
Best regards from France,
Fabrice Etanchaud
[1] http://docs.basex.org/wiki/Indexes#Updates
*De :* BaseX-Talk [mailto:basex-talk-bounces@mailman.uni-konstanz.de] *De la part de* ???????? ???????? *Envoyé :* jeudi 21 juin 2018 16:02 *À :* BaseX *Objet :* [basex-talk] Full-Text
Hi, everyone!
Is there any way to index only imported xml-files?
Now, when I import xml-files the full-text index is deleted.
After importing I recreate whole full-text index and it takes too much time :(
--
С уважением,
Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
-- s0rr0w
-- С уважением, Ветошкин Владимир Владимирович
-- s0rr0w
-- С уважением, Ветошкин Владимир Владимирович
Hi Vladimir,
But if I search in "db:list...db:open..." - it takes about 12-15 seconds.
If the name of the database is not statically known, the query cannot be rewritten for index access (because one the targeted database may not have the required index). I guess you have the full-text index enabled?
However, since BaseX 9, you can take advantage of the ENFORCEINDEX option: All queries will then optimized for index operations, based on your knowledge that there an index will be available. See [1] for further details.
By the way, you can have a look at the compilation section of the Info View in the GUI to see if indexes will be applied in your query.
Best, Christian
[1] http://docs.basex.org/wiki/Indexes#Enforce_Rewritings
Example takes ~12-15s: let $db := for $i in db:list()[starts-with(.,'000999~')] return try {db:open($i)} catch * {} for $doc in $db/.//*[text() contains text { 'TEN-9258' } any] return $doc
Example takes ~180ms (returns 2 rows): let $db := for $i in db:list()[starts-with(.,'000999~201807')] return db:open($i) for $doc in $db/.//*[text() contains text { 'TEN-9258' } any] return $doc
Example takes ~10ms (returns 2 rows): for $doc in db:open('000999~201807')/.//*[text() contains text { 'TEN-9258' } any] return $doc
Why do the last 2 examples take different times? How can I improve this?
Example takes ~2s (returns 0 rows): let $db := for $i in db:list()[starts-with(.,'000999~201806')] return db:open($i) for $doc in $db/.//*[text() contains text { 'TEN-9258' } any] return $doc
Example takes ~12ms (returns 0 rows): for $doc in db:open('000999~201806')/.//*[text() contains text { 'TEN-9258' } any] return $doc
25.06.2018, 13:07, "Alexander Shpack" shadowkin@gmail.com:
Hi, Vladimir,
If you will do db names with the particular prefix, for example "db_", you may use the next code
let $docs := for $i in db:list()[starts-with(.,"db_")] return db:open($i)return $docs/*
On Mon, Jun 25, 2018 at 12:32 PM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Alexander,
Some questions: After that, how can I perform a search in all of these databases? Can I search for substring without fulltext using only text index?
25.06.2018, 11:56, "Alexander Shpack" shadowkin@gmail.com:
Hey Vladimir,
You can use sharding approach for you data import and split all DBs even every month.
On Mon, Jun 25, 2018 at 11:50 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Alexander! Thank you!
In my previous letter I have described the proccess in short. I'll think about separated DB. But I'm afraid that this base will also be very big in future. Although I can try to split data to several databases - one per year.. Hmm..
25.06.2018, 11:25, "Alexander Shpack" shadowkin@gmail.com:
Hey, Vladimir!
Just put this specific files to the separated DB and than index it. You can process it automatically, BaseX allows to create and index DB right from XQuery.
I hope it helps you. Anyhow, you can provide more details about your task and we can figure out the best solution for you.
On Mon, Jun 25, 2018 at 10:42 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Hi, Fabrice! Thank you.
All databases constantly change.That is why there is no way to single out "a big readonly collection" :( Maybe it is possible to use some other incremental indexes? I have to index specific xml-files, not all files in database.
21.06.2018, 17:16, "Fabrice ETANCHAUD" fetanchaud@pch.cerfrance.fr:
Hi Vladimir,
I don’t think there is something like a incremental full text index for the moment [1].
As index is per collection, the recommanded way shall be to split your data in two collections :
A big readonly collection of all the past updates, indexed onceA small/medium sized collection whom full text index can be recreated in an acceptable time after each update.At the end of a predefined time period, you have to add the live collection to the readonly one, reindex it, and truncate the live one.
Best regards from France,
Fabrice Etanchaud
[1] http://docs.basex.org/wiki/Indexes#Updates
De : BaseX-Talk [mailto:basex-talk-bounces@mailman.uni-konstanz.de] De la part de ???????? ???????? Envoyé : jeudi 21 juin 2018 16:02 À : BaseX Objet : [basex-talk] Full-Text
Hi, everyone!
Is there any way to index only imported xml-files?
Now, when I import xml-files the full-text index is deleted.
After importing I recreate whole full-text index and it takes too much time :(
--
С уважением,
Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
-- s0rr0w
-- С уважением, Ветошкин Владимир Владимирович
-- s0rr0w
-- С уважением, Ветошкин Владимир Владимирович
-- s0rr0w
-- С уважением, Ветошкин Владимир Владимирович
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs for $doc in db:open($db)/.//*[(# db:enforceindex #) { text() contains text { 'TEN-9258' } any }] return $doc
Maybe you’ll have to use the pragma on top of your expression:
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text 'TEN-9258'] }
As you may have seen, I have simplified `/.//*` to `//*` (but maybe it was optimized to this representation anyway).
Cheers, Christian
These examples work differently.
So If I read this correctly, the number of results for 1. is still identical, right? However, in the second query in 2., no results are returned. You could report the query plan will give us some insight into what happens here.
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text { 'болт' } any] } 378 rows
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs let $ft := ft:search($db, "болт")/parent::* for $node in $ft return $node 378 rows
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text { 'автомобиль' } any] } 0 rows
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs let $ft := ft:search($db, "автомобиль")/parent::* for $node in $ft return $node 2138 rows
Why do they work differently?
I think I found the missing pieces:
• In your full-text index, you used non-default options (which is completely fine) • In the rewritten query, these options cannot applied to your query (because, once again, they are not known at compile time).
Your query should yield the expected results if you add the options to your full-text expression:
(# db:enforceindex #) { for $db in db:list()[starts-with(., 'x')] return db:open($db)//*[text() contains text 'автомобиль' using stemming using language 'ru'] }
I added a note in our documentation [1]. Another option is (as you already found out) to directly use ft:search.
Cheers, Christian
[1] http://docs.basex.org/wiki/Indexes#Enforce_Rewritings
On Fri, Jul 20, 2018 at 11:54 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Query plan (0 rows):
<QueryPlan compiled="true" updating="false"> <Extension type="element()*"> <DBPragma value=""> <QNm type="xs:QName">db:enforceindex</QNm> </DBPragma> <GFLWOR type="element()*"> <For type="xs:string" size="1"> <Var name="$db" id="0" type="xs:string"/> <IterFilter type="xs:string*"> <DbList name="list([database[,path]])" type="xs:string*"/> <FnStartsWith name="starts-with(string,sub[,collation])" type="xs:boolean" size="1"> <ContextValue type="xs:string" size="1"/> <Str type="xs:string">000999~</Str> </FnStartsWith> </IterFilter> </For> <CachedPath type="element()*"> <FTIndexAccess type="text()*"> <IndexDynDb> <DbOpen name="open(database[,path])" type="document-node()*"> <VarRef type="xs:string" size="1"> <Var name="$db" id="0" type="xs:string"/> </VarRef> </DbOpen> </IndexDynDb> <FTWords type="xs:boolean" size="1"> <Str type="xs:string">автомобиль</Str> </FTWords> </FTIndexAccess> <IterStep axis="parent" test="*" type="element()*"/> </CachedPath> </GFLWOR> </Extension> </QueryPlan>
And query plan (2138 rows):
<QueryPlan compiled="true" updating="false"> <GFLWOR type="element()*"> <Let type="xs:string*"> <Var name="$dbs" id="0" type="xs:string*"/> <IterFilter type="xs:string*"> <DbList name="list([database[,path]])" type="xs:string*"/> <FnStartsWith name="starts-with(string,sub[,collation])" type="xs:boolean" size="1"> <ContextValue type="xs:string" size="1"/> <Str type="xs:string">000999~</Str> </FnStartsWith> </IterFilter> </Let> <For type="xs:string" size="1"> <Var name="$db" id="2" type="xs:string"/> <VarRef type="xs:string*"> <Var name="$dbs" id="0" type="xs:string*"/> </VarRef> </For> <Let type="element()*"> <Var name="$ft" id="3" type="element()*"/> <CachedPath type="element()*"> <FtSearch name="search(database,terms[,options])" type="text()*"> <VarRef type="xs:string" size="1"> <Var name="$db" id="2" type="xs:string"/> </VarRef> <Str type="xs:string">автомобиль</Str> </FtSearch> <IterStep axis="parent" test="*" type="element()*"/> </CachedPath> </Let> <VarRef type="element()*"> <Var name="$ft" id="3" type="element()*"/> </VarRef> </GFLWOR> </QueryPlan>
20.07.2018, 12:47, "Christian Grün" christian.gruen@gmail.com:
These examples work differently.
So If I read this correctly, the number of results for 1. is still identical, right? However, in the second query in 2., no results are returned. You could report the query plan will give us some insight into what happens here.
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text { 'болт' } any] } 378 rows
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs let $ft := ft:search($db, "болт")/parent::* for $node in $ft return $node 378 rows
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text { 'автомобиль' } any] } 0 rows
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs let $ft := ft:search($db, "автомобиль")/parent::* for $node in $ft return $node 2138 rows
Why do they work differently?
-- С уважением, Ветошкин Владимир Владимирович
This seems to be a limitation of the Russian stemmer implementation, which we took from the Apache Lucene project. Maybe we could replace it with a more sophisticated implementation. Do you have some experience with other stemmers that are available in the wild?
Ветошкин Владимир en-trance@yandex.ru schrieb am So., 22. Juli 2018, 14:30:
Hi!
After some tests of search (using stemming, using language ru) I have found several problems. E.g.: if search for "кузов" - it doesn't find "кузова"
20.07.2018, 14:26, "Ветошкин Владимир" en-trance@yandex.ru:
Christian, you're genius :) Thank you very much for your help!
20.07.2018, 14:19, "Christian Grün" christian.gruen@gmail.com:
I think I found the missing pieces:
• In your full-text index, you used non-default options (which is completely fine) • In the rewritten query, these options cannot applied to your query (because, once again, they are not known at compile time).
Your query should yield the expected results if you add the options to your full-text expression:
(# db:enforceindex #) { for $db in db:list()[starts-with(., 'x')] return db:open($db)//*[text() contains text 'автомобиль' using stemming using language 'ru'] }
I added a note in our documentation [1]. Another option is (as you already found out) to directly use ft:search.
Cheers, Christian
[1] http://docs.basex.org/wiki/Indexes#Enforce_Rewritings
On Fri, Jul 20, 2018 at 11:54 AM Ветошкин Владимир en-trance@yandex.ru wrote:
Query plan (0 rows):
<QueryPlan compiled="true" updating="false"> <Extension type="element()*"> <DBPragma value=""> <QNm type="xs:QName">db:enforceindex</QNm> </DBPragma> <GFLWOR type="element()*"> <For type="xs:string" size="1"> <Var name="$db" id="0" type="xs:string"/> <IterFilter type="xs:string*"> <DbList name="list([database[,path]])" type="xs:string*"/> <FnStartsWith name="starts-with(string,sub[,collation])" type="xs:boolean" size="1"> <ContextValue type="xs:string" size="1"/> <Str type="xs:string">000999~</Str> </FnStartsWith> </IterFilter> </For> <CachedPath type="element()*"> <FTIndexAccess type="text()*"> <IndexDynDb> <DbOpen name="open(database[,path])" type="document-node()*"> <VarRef type="xs:string" size="1"> <Var name="$db" id="0" type="xs:string"/> </VarRef> </DbOpen> </IndexDynDb> <FTWords type="xs:boolean" size="1"> <Str type="xs:string">автомобиль</Str> </FTWords> </FTIndexAccess> <IterStep axis="parent" test="*" type="element()*"/> </CachedPath> </GFLWOR> </Extension> </QueryPlan>
And query plan (2138 rows):
<QueryPlan compiled="true" updating="false"> <GFLWOR type="element()*"> <Let type="xs:string*"> <Var name="$dbs" id="0" type="xs:string*"/> <IterFilter type="xs:string*"> <DbList name="list([database[,path]])" type="xs:string*"/> <FnStartsWith name="starts-with(string,sub[,collation])" type="xs:boolean" size="1"> <ContextValue type="xs:string" size="1"/> <Str type="xs:string">000999~</Str> </FnStartsWith> </IterFilter> </Let> <For type="xs:string" size="1"> <Var name="$db" id="2" type="xs:string"/> <VarRef type="xs:string*"> <Var name="$dbs" id="0" type="xs:string*"/> </VarRef> </For> <Let type="element()*"> <Var name="$ft" id="3" type="element()*"/> <CachedPath type="element()*"> <FtSearch name="search(database,terms[,options])" type="text()*"> <VarRef type="xs:string" size="1"> <Var name="$db" id="2" type="xs:string"/> </VarRef> <Str type="xs:string">автомобиль</Str> </FtSearch> <IterStep axis="parent" test="*" type="element()*"/> </CachedPath> </Let> <VarRef type="element()*"> <Var name="$ft" id="3" type="element()*"/> </VarRef> </GFLWOR> </QueryPlan>
20.07.2018, 12:47, "Christian Grün" christian.gruen@gmail.com:
These examples work differently.
So If I read this correctly, the number of results for 1. is still identical, right? However, in the second query in 2., no results are returned. You could report the query plan will give us some insight into what happens here.
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text { 'болт' } any] } 378 rows
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs let $ft := ft:search($db, "болт")/parent::* for $node in $ft return $node 378 rows
(# db:enforceindex #) { for $db in db:list()[starts-with(.,'000999~')] return db:open($db)//*[text() contains text { 'автомобиль' } any] } 0 rows
let $dbs := for $i in db:list()[starts-with(.,'000999~')] return $i for $db in $dbs let $ft := ft:search($db, "автомобиль")/parent::* for $node in $ft return $node 2138 rows
Why do they work differently?
-- С уважением, Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
-- С уважением, Ветошкин Владимир Владимирович
basex-talk@mailman.uni-konstanz.de
-
Alexander Shpack -
Christian Grün -
Fabrice ETANCHAUD -
Ветошкин Владимир