Spectrophotometric determination of gold with 2-hydroxymethyl-6-(2′-hydroxymethyl-5′-hydroxy-4′-pyrone-6′)-pyranyl[3,2-b]pyran-4,8-dione. Fresenius' Zeitschrift
Society, London, 1958. Yabuta T. The constitution of kojic acid, a gamma-pyrone derivative formed by Aspergillus oryzae from carbohydrates. Journal of the