1. Shelimov, B.N., Unconventional methods of activation of oxide catalysts, with supported transition metal ions, Ross. Khim. Zh., 2000, vol. 44, p. 57.
2. Romenskii, A.V., Volokhov, I.V., and Loboiko, A.Ya., Mechanism of the formation of active sites in a catalyst exposed to an ultrasonic field, Khim. Tekhnol., 1986, no. 6, p. 39.