Clinica Chimica Acta, 521, 70-75. Elsevier van Winden, L J, Lanfermeijer, M, Heijboer, A C, van Tellingen, O, Bergman, A M, van der Poel, H G, Jonker, N & van Rossum, H H 2021, ' Retrospective analysis of serum testosterone levels by LC-MS/MS in chemically castrated prostate cancer patients: Biological variation and analytical performance specifications ', Clinica Chimica Acta, vol. 521, pp. 70-75 . https://doi.org/10.1016/j.cca.2021.06.030 Clinica chimica acta; international journal of clinical chemistry, 521, 70-75. Elsevier