Thank you so much for the recent Belaieff postings - a publisher of works I have been hunting down for many years. There is a beautiful publication which details many Belaieff scores, their gorgeous front covers and the histories of the relative composers: The Beauty Of Belaieff by Richard Beattie Davis [publisher: G-Clef Publishing]. It is rather expensive but an exquisite and very informative book.
Out of interest...and being very cheeky, the following are Bealieff scores I have been trying to trace and, no doubt would be a much valued contribution to everyone....just in case you discover any copies in your searches

Akimenko - Op 21 Cinq Morceaux
Alpheraky - Op 21 Trois Morceaux; Op 27 Trois Morceaux, Op 29 Trois Morceaux & Op 30 Trois Morceaux
Blumenfeld S - Op 2 Quasi mazurka
Dreyer Op 2 Badinage Muscial & Op 4 Prelude et Etude
Glazunov - Op 1 Andante from 1st quartet arr. piano solo; Op 10 2nd quartet arr. piano solo; Op 38 In moddo religioso arr. pianosolo; Op 40 Marche triomphale arr. paino solo
Khvostchinsky Op 13 Deux Preludes
Pogojeff Op 1 Cinq Fugues, Op 2 Quatre Fugues & Op 4 Six Preludes
Stcherbatcheff N - Op 31 La melancolie, Op 33 Serenade; Op 34 Valse-Entr'acte, Op 36 Les adieux, Op 42 Mazura
Steinberg - Op 7 Prelude symphonique arr. piano solo, Op 10 Les metamorphoses arr. piano solo
Winkler - Op 6 Trois Morceaux
...plus there are many orchestral and chamber works arranged for piano / 4 hands.
Many thanks again....your contribution is always much admired and appreciated.
Malcolm