1. Aoac 1975: Official methods of analysis of the AOAC 12th Ed. Washington D. C.
2. Nitratbestimmung in Pflanzensubstanz mit 1.2.4–Xelenol;Balks R.;Landw. Forschung,1960
3. Relation of calcium content and nature of the pectic substances in bean hypocotyls of different ages to susceptibility to an isolate of Rhizcotonia solani;Bateman D. F.;Phytopathology,1965