1. AOAC (Association of Official Analytical Chemists), 2002. Appendix D: Guidelines for Collaborative Study Procedures To Validate Characteristics of a Method of Analysis. AOAC Official Methods of Analysis.
2. Determination of the stability of antibiotics in matrix and reference solutions using a straightforward procedure applying mass spectrometric detection;Berendsen;Food Additives & Contaminants Part A,2011
3. BfR (Bundesinstitut für Risikobewertung), 2013. Scientific opinion. Available from: http://www.bfr.bund.de/cm/349/pyrrolizidinealkaloids‐in‐herbal‐teas‐and‐teas.pdf
4. BfR (Bundesinstitut für Risikobewertung), 2015. International collaborative study for the Determination of pyrrolizidine alkaloids in honey and herbal tea by SPE‐LC‐MS/MS. Available from: http://www.bfr.bund.de/cm/350/international‐collaborative‐study‐for‐the‐determination‐of‐pyrrolizidine‐alkaloids‐in‐honey‐and‐herbal‐tea‐by‐spe‐lc‐ms‐ms.pdf
5. Determination of pyrrolizidine alkaloids in tea, herbal drugs and honey;Bodi;Food Additives & Contaminants: Part A,2014