GB patent 191008,Layraud, E.,「The manufacture of unsymmetrical c.c.-dialkylbarbituric acids」,发行于1923-10-25
US patent 1856792,Shonle, H. A.,「Anhydrous alkali salts of 5,5-di-aliphatic-substituted barbituric acids and processes of producing them」,发行于1932-05-03