1. Skim milk powder;ADPI,2016
2. Nonprotein nitrogen in whole milk. Kjeldahl method, method no. 991.21;AOAC,2012
3. TCA precipitated protein nitrogen content of milk. Kjeldahl method, method no. 991.22;AOAC,2012
4. Protein nitrogen content of milk. Indirect kjeldahl method, method no. 991.23;AOAC,2012
5. Nitrogen (total) in milk ‒ Kjeldahl methods, method no. 991.20;AOAC,2012