1. Crustal abundance of elements and mineral reserves and, resources;Erickson;U.S. Geological Survey, Professional Paper 820,1973
2. An abundance model resource appraisal for some Canadian commodities;Garett;Int. Assoc. Math. Geol. J.,1978
3. Defining and measuring world mineral supplies;Govett,1976
4. The appraisal of mineral resources;Harris,1981
5. Numerical Petrology;LeMaitre,1982