We could only find a few related materials in either language.

* Russian lecture: conversational systems, seq2seq vs ranking, DSSM - [video](https://www.youtube.com/watch?v=n-mNWacDKUQ)

* English lecture: advanced NLP applications, subword units, DSSM - [video](https://www.youtube.com/watch?v=D4JnoOAihII)

* Siamee networks explained - [url](https://www.quora.com/What-are-Siamese-neural-networks-what-applications-are-they-good-for-and-why) (see first reply by Pond-Premtoon)

* DSSM materials by Microsoft Research - [url](https://www.microsoft.com/en-us/research/project/dssm/)