1. Krevelen van, D.W. and Schuijer, J., Coal Science: Aspects of Coal Constitution, Amsterdam: Elsevier, 1957.
2. Shaw, D.N., Interpretation Geochimique des Elements en Traces dans les Roches Cristallines, Paris: Masson, 1964.
3. Asuen, C.C., Die Koncentration der chemischen Elements und ihren Bezeichungen, Chem. Erde, 1968, vol. 4, pp. 321–332.
4. Gol’dshmidt, V.M., Sbornik statei po geokhimii redkikh elementov (Collection of Research Works on Geochemistry of Rare Elements), Moscow: Gos. Ob”ed. Nauchno-Tekh. Izd., 1938.
5. Lyakhov, V.V., Redkie elementy v porodoobrazuyushchikh mineralakh granitoidov (Rare Elements in the Rock-Forming Minerals of Granitoids), Moscow: Nedra, 1972.