1. S. P. Lyakh and E. L. Ruban, Microbial Melanins [in Russian], Moscow (1972).
2. S. P. Lyakh, Microbial Melaninogenesis and Its Functions [in Russian], Moscow (1981).
3. R. A. Nicolaus, Melanins, Paris (1968).
4. R. A. Nicolaus, Rass. Med. Specim. Suppl.,9, 1 (1962).
5. E. L. Ruban and S. P. Lyakh, Izv. Akad. Nauk SSSR, Ser. Biol., No. 4, 530 (1968).