1. A study of the strength of coal pillars;Salamon;J S Afr Inst Min Metall,1967
2. A hypothesis concerning pillar stability;Wilson;Min Eng,1972
3. A review of coal pillar strength formulas;Hustrulid;Rock Mech Rock Eng,1976
4. Pariseau WG, Hustrulid WA, Swanson SR, Van Sambeek LL. Coal pillar strength study: the design of production pillars in coal mines (Final report, Contract HO242059 in situ coal pillar strength study). Salt Lake City: University of Utah; 1977.
5. Mark C, Iannacchione AT. Coal pillar mechanics: theoretical models and field measurements compared. In: Proceedings of the workshop on coal pillar mechanics and design. Pittsburgh: US Department of the Interior. Bureau of Mines; 1992, p. 78–93.