Não informado. (1967). Phosphorus in agriculture. International Superphosphate and Compound Manufacturers Association.
Chicago-referens (17:e uppl.)Não informado. Phosphorus in Agriculture. London: International Superphosphate and Compound Manufacturers Association, 1967.
MLA-referens (8:e uppl.)Não informado. Phosphorus in Agriculture. International Superphosphate and Compound Manufacturers Association, 1967.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.