Não informado. (1967). Phosphorus in agriculture. International Superphosphate and Compound Manufacturers Association.
Lua i Stíl Chicago (17ú heag.)Não informado. Phosphorus in Agriculture. London: International Superphosphate and Compound Manufacturers Association, 1967.
Lua MLA (8ú heag.)Não informado. Phosphorus in Agriculture. International Superphosphate and Compound Manufacturers Association, 1967.
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