1. Determination of total nitrogen in natural waters by means of persulphate oxidation;Koroleff,1972
2. Determination of dissolved inorganic phosphorus;Koroleff,1972
3. Total and organic nitrogen;Koroleff,1976
4. Determination of total phosphorus;Koroleff,1976
5. Simultaneous persulphate oxidation of phosphorus and nitrogen compounds in water;Koroleff,1977