937, 939 & 945 are recordings of the cornetist Fritz Werner (of the Berlin Court Opera House), who possibly also plays in Kamionsky's accompanying "orchestra" on 940 - 942.
Actually Fritz Werner was member of the Wiesbaden Court Opera House which was "affiliated" to the Berlin one. But there is no clue for Wiesbaden as recording place.
Thank you for the information! Most likely you are right.
Look at this magazine, page 13. There is bilingual article about Anker-Record. Unfortunately, it has a lot of emotions and a few facts. However, the article makes it clear that its author Philipp Kroll can not be Anker-Record recording engineer as it is stated in the P.N.Grünberg book.
There is another mistake in Grünberg book - the Anker-Record records appeared on Russian market much earlier than 1910. The first mentioning I found in the The Gramophone News magazine, ¹1, April 1907, page 20 where it said that the price of Anker-Record records is 1 Ruble 75 kopeks for single-sided grand, 2 Rubles 50 kopeks for double-sided grand.
