1. G. N. Kuznetsov, Mechanical Properties of Rocks [in Russian], Moscow, Ugletekhizdat (1947).
2. K. V. Ruppeneit, Mechanical Properties of Rocks [in Russian], Moscow, Ugletekhizdat (1956).
3. Investigation of the Mechanical Properties of Rocks of the Donets Basin [in Russian], Moscow, Ugletekhizdat (1951).
4. O. Müller, Untersuchengen an Karbongestein zur Klärung von Gebiergdruckfragen. No. 47-48 (1930).
5. D. W. Phillips, Colliery Engng. (VI, VIII–XI) (1948).