1. ISO 5725–2:2019. Accuracy (trueness and precision) of measurement methods and results—Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method.
2. ISO-Guide 35:2017. Reference materials—Guidance for characterization and assessment of homogeneity and stability.
3. 2019/1009/EU 2019 Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003. EC (ed).
4. AbfKlärV 2017 German sewage sludge directive (Verordnung zur Neuordnung der Klärschlammverwertung). Bundesregierung (ed) Bonn.
5. Baralkiewicz D, Gramowska H, Hanc A, Krzyzaniak I (2007) A comparison of ICP-OES and ICP-MS in the determination of elements in lake water. Atom Spectrosc 28(5):164–170