1. M. A. Zubaschenko, Izv. Voronezh. Otd. Geogr. O-va SSSR, No. 3, 159–166 (1961).
2. M. A. Zubaschenko, Gidrogeol. Karstoved., No. 2, 157–168 (Perm, 1964).
3. M. A. Zubaschenko, Nauch. Zap. Voronezh. Otd. Geogr. O-va SSSR, No. 1, 97–100 (1970).
4. Doan Dinh Thai, Regularities of the distribution and development of karst in North Vietnam, Candidate’s Dissertation in Geology and Mineralogy (Sergo Ordzhonikidze Russian State Univ. Geol. Prospect., Moscow, 1990).
5. R. L. Ciochon and J. W. Olsen, Bull. Indo-Pacific Prehist. Assoc. 10, 59–73 (1991).