found: Verdi, G. Don Carlo [SR] 1955: label (Elena Nicolai, mezzo-sop.)
found: New Grove opera (Nicolai, Elena (Nikolova, Elena Stoianka); b. Cerevo, nr Pazordžik, 1-24-05; Bulgarian mezzo-soprano)
found: Opera, Jan. 1994: p. 45 (Elena Nicolai; b. Elena Stoianka Nikolova, Cerevo, Bulgaria, 1-24-1905; d. Milan, 10-24-1993, aged 88; Italian mezzo-soprano of Bulgarian origin)
found: Diz. enc. universale della mus. e dei musicisti (Nicolai, Elena; real name Nicolova Stojanca Savova; Bulgarian contralto; b. 24-I/6-II-1912, Sofia)
found: Kutsch/Riemens, 1987- (Nicolai, Elena; b. 9-26-12, Sofia; alto; real name Elena Stoianka)
found: Muz. ėnt͡s. (Nikolaĭ, Elena (Stoi͡anka Nikolova))
found: Riemann Musik Lexikon, 12. Aufl.: Suppl. (Nikolaj, Elena (Nicolai); real name Stojanka Savova Nikolova; b. 1-24(2-6) 1905, Cerovo; Bulgarian mezzo-soprano)
Nicolai, Elena
