1. The role of bentonite in soil sealing applications;Alther;Bull. Assoc. Eng. Geol.,1982
2. “Improvement” of drilling mud properties of low grade bentonites by simultaneous chemical activation and compaction;Alther;Interceram,1982
3. Inorganic permeant effects upon bentonite;Alther,1985
4. API Specification for Oil Well Drlling Fluid Materials;American Petroleum Institute,1979
5. Activation of non swelling bentonite;Bleifuss;Clay Miner.,1973