M. Biendl and B. Foster, “New International Calibration Standard (ICS-I4) for HPLC Analysis of Iso-α-acids: Submitted on behalf of the International Hop Standards Committee”, BrSc, vol. 70, no. 11/12, p. 176, Dec. 2017, Accessed: Jun. 25, 2026. [Online]. Available: https://brewingscience.de/index.php/brewingscience/article/view/331