LEMPERT, K., K. ZAUER, and J. BREUER. 1964. “HYDANTOINS, THIOHYDANTOINS, GLYKOCYAMIDINES. XVll : THE REACTION OF S,S’-DIMETHYL-5,5-DIPHENYL-DITHIOHYDANTOIN AND S-METHYL-5,5-DIPHENYL-4-THIOHYDANTOIN WITH OXO REAGENTS AND POTASSIUM HYDROGENE SULFIDE”. Periodica Polytechnica Chemical Engineering 8 (1):21-28.