Biendl, M., et al. “Determination of Iso-Alpha-Acids, Alpha- and Beta-Acids in Isomerised Hop Pellets by HPLC: Submitted on Behalf of the EBC Analysis Committee”. BrewingScience, vol. 57, no. 7/8, Aug. 2004, pp. 54-55, https://brewingscience.de/index.php/brewingscience/article/view/556.