Thomas, L.C.
Colorimetric chemical analytical methods
John Wiley & Sons, 1980
 Buku Teks
Simpson, George Gaylord, editor
Why and how : some problems & methods in historical biology/ George Gaylord Simpson
Pergamon Press, 1980
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McNeill, Patrick
Research methods
Routledge, 1990
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Numerical methods
edited by P. Rozsa
North-Holland, 1980
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Snedecor, George W.
Statistical methods
Iowa State University Press, 1989
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