ISO 8968-4:2016 牛奶和奶制品. 氮含量的測定. 第4部分: 蛋白質和非蛋白質氮含量的測定和純蛋白質含量的計算 (參考方法)
Milk and milk products - Determination of nitrogen content - Part 4: Determination of protein and non-protein nitrogen content and true protein content calculation (Reference method)