1. Gypsum & anhydrite;Grooves,1958
2. Brookby HE. US patent 1,370,581, March 8; 1931.
3. Hoggart GA. US patent 1,960,538, May 29; 1934.
4. Randel WS, Dailey MC. US patent 1,901,051, March 14; 1933. 1931, 240, October 17; 1933.
5. Autoclaved gypsum plaster from selenite and by-product phosphogypsum;Singh;J ChemTech Biotechnol,1988