1. Persulfate digestion for determination of total nitrogen and phosphorus in low-nutrient waters;Ameel;Am. Environ. Lab.,1993
2. Neue Methode zur Bestimmung des Stickstoffs in organischen Körpern;Kjeldahl;Zeitschrift für analytische Chemie,1883
3. Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory: Evaluation of Alkaline Persulfate Digestion as an Alternative to Kjeldahl Digestion for Determination of Total and Dissolved Nitrogen and Phosphorus in Water;Patton,2003
4. Simultaneous determination of total nitrogen and total phosphorus in environmental waters using alkaline persulfate digestion and ion chromatography;De Borba;J. Chromatogr. A,2014
5. Introducing a New ASTM Method for the Determination of Total Nitrogen, and TKN by Calculation, in Water Samples | Environmental XPRT, n.d. https://www.environmental-expert.com/articles/introducing-a-new-astm-method-for-the-determination-of-total-nitrogen-and-tkn-by-calculation-in-wate-697720. (Accessed 21 October 2019).