Geokhimi︠i︡a, mineralogi︠i︡a i litologi︠i︡a chernykh slan︠t︡sev : sbornik nauchnykh trudov - ︠I︡Udovich, ︠I︡Akov Ėlʹevich; Silaev, V. I. (Valeriĭ Ivanovich) (Komi filial AN SSSR, 1987)