Biendl, M. “Determination of Hop Oil Content by Steam Distillation According to IOB Method 6.3: Submitted on Behalf of the Analysis Committee of the European Brewery Convention”. BrewingScience, vol. 55, no. 11/12, Dec. 2002, p. 234, https://brewingscience.de/index.php/brewingscience/article/view/590.