Four songs for low voice and piano :
(original keys) : op. 39 /
by Nikolai Rimsky-Korsakov.

APA Citation

Rimsky-Korsakov, N., Tolstoy, A. Konstantinovich. (2001). Four songs for low voice and piano: (original keys) : op. 39. Boca Raton, Fla.: Masters Music Publications.

MLA Citation

Rimsky-Korsakov, Nikolay, 1844-1908, and Aleksey Konstantinovich Tolstoy. Four Songs for Low Voice And Piano: (original Keys) : Op. 39. Boca Raton, Fla.: Masters Music Publications, 2001.

Warning: These citations may not always be complete (especially for serials).