Wagner Chemiker-Zeitung, Chemische Apparatur, 1928 , vol. 52, p. 379 Chem. Zentralbl., 1928 , vol. 99, # I p. 3056 Full Text Show Details Stockelbach Patent: US1792716 , 1927 ; Full Text Show Details Stockelbach Patent: US1792717 , 1927 ; Full Text Show Details Boedecker Patent: US1812132 , 1926 ; Full Text Show Details Riedel-de Haen Patent: DE505404 , 1925 ; Fortschr. Teerfarbenfabr. Verw. Industriezweige, vol. 17, p. 569,18 571 Full Text Show Details Riedel-de Haen Patent: DE539880 , 1925 ;