The Russian Imperial Singers were five voices: a first tenor, a second tenor, a baritone, a basso and a basso profunde. The baritone Stephen Slepoushkin was the leader of the group.
First Tenor: Michael Dido
Second Tenor: Demetre Criona
Baritone: Stephen Slepoushkin
Basso: Andrew Grigorieff
Basso Profundo: Ierimarh Zragewski
PIano: Jascha Zayda
Oswego Palladium-Times, Wednesday January 29, 1936
"Richard K. Spottswood. A Discography of Ethnic Recordings Produced in the United States, 1893 to 1942":
RUSSIAN IMPERIAL SINGERS
64679-B Kanavka-Moscow Street Songs De 2514
64680-A Pt. 1 De 2515
64681-A Pt. 2 De 2516
64682- Snowball Tree De rej
64683-A Grandfather Pahom De 2518
64684-A De 2516
NY "October 4, 1938"
64685-A De 2514
64686-B Vetserni Zvon De 2518
64687- De rej
64688- De rej
64689-A De 2519
64690-A De 2517
64691-A De 2515
NY "October 5, 1938"
64744-A Snowball Tree De 2517
64745-A Domashnaia Ssora Dargomijsky De 2519
NY "November 16, 1938"
The above are included in album 53.