1. Mel'nikov, B.P. and Kudryavtseva, I.A., Proizvodstvo mocheviny (Production of Urea), Moscow: Khimiya, 1965.
2. Kuznetsova, M.N. and Bergman A.G., Zh. Obshch. Khim., 1956, vol. 26, pp. 1326–1329.
3. Bokhovina, I.M., Bokhovin, Yu.I., and Usplyanina, L.S., Zh. Obshch. Khim., 1964, vol. 34, pp. 1375–1379.
4. Dalman, L.H., J. Am. Chem. Soc., 1937, vol. 56, pp. 559–562.
5. Kucheryavyi, V.I. and Lebedev, V.V., Sintez i primenenie mocheviny (Synthesis and Use of Urea), Leningrad: Khimiya, 1970.