Principles and practice of agricultural analysis. Volume 2 (of 3), Fertilizers

by Harvey Washington Wiley

[15] Vid. op. et loc. cit. 13.

[16] U. S. Geological Survey, Bulletin No. 47.

[17] Vid. op. et loc. cit. 14.

[18] Vid. op. et loc. cit. 13.

[19] Vid. op. cit. 14, p. 147.

[20] Transactions of the American Institute of Mining Engineers, Vol. 21, p. 168.

[21] Phosphates of America, p. 153.

[22] Die Landwirtschaftlichen Versuchs-Stationen, Band 34, S. 379.

[23] Zeitschrift für analytische Chemie, 1892, S. 383.

[24] Zeitschrift für angewandte Chemie, 1894, Ss. 679 und 701.