1. Official Methods of Analysis;AOAC,1965
2. The effect of inoculation by nodule bacteria and nitrogen fertilization on growth, yield and nitrogen content of soybean plants;Ashour,1969
3. The kjeldahl method for organic nitrogen;Bradstreet,1965
4. Multiple range and multiple F test;Duncan;Biometrics,1955
5. Dry matter accumulation patterns in determinate and indeterminate soybeans;Egli;Crop Sci.,1973