Münz, Ferdinand; Alder, Kurt (1949). "Diensynthese und substituierende Addition beim Divinyl-methan-typus Addition von Maleinsäure-anhydrid an Pentadien-1,4 und an 1,4-Dihydro-benzol". Justus Liebigs Ann. Chem. 565: 126–135. doi:10.1002/jlac.19495650113.
espacenet.com
worldwide.espacenet.com
US 2130505, Münz, Ferdinand, "Polyamino carboxylic acids and process of making same", published 1938-09-20, assigned to General Analine Works, Inc.