1. Trace Elements in Soils;Aubert,1977
2. Pedology, Weathering and Geomorphological Research;Birkland,1974
3. Methods of Chemical Analysis of Soils;Blakemore;N.Z. Soil Bur. Sci. Rep., 10A. N.Z. Soil Bur.,1972
4. Copper deficiency in crops;Caldwell,1971
5. Micronutrient soil tests;Cox,1972