Wiki information Boltovskoi:

D. D. Morduhai-Boltovskoi
Mathematician, Person, Deceased Person

Dmitry Dmitrievich Morduhai-Boltovskoi was a Russian mathematician, best known for his work in analysis, differential Galois theory, number theory, hyperbolic geometry, and history of mathematics. He is also known for his annotated translation of...

Konstantin Posse
Deceased Person, Person

Konstantin Alexandrovich Posse was a Russian mathematician know for contributions to analysis and in particular approximation theory. Veniamin Kagan and D. D. Morduhai-Boltovskoi were among his students.