1. Al Abbasi, J. N. and Fahmi, K. J.: 1991, Gempak: a Fortran-77 program for calculating Gumbel's first, third, and mixture upper earthquake magnitude distributions employing maximum likelihood estimation,Comput. Geosc. 17, 271?290.
2. Algermissen, S. T., Perkins, D. H., Isherwood, W., Gordon, D., Reagot, G., and Howard, C.: 1976, Seismic risk evaluation of the Balkan region, in V. Karnik and C. Radu (eds.),Proc. Seminar on Seismic Zoning Maps, UNESCO, Skopje, vol. 2, pp. 173?240.
3. Boccaletti, M., Manetti, P., and Peccerillo, A.: 1974, The Balkans as an instance of back-arc thrust belt: possible relation with the Hellenids,Geol. Soc. Am. Bul. 85, 1077?1084.
4. Bonchev, Ek., Bune, V. I., Christoskov, L., Karajuileva, J., Kostadinov, V., Reisner, G. I., Rizhikova, S., Shebalin, N. V., Sholpo, V. N., and Sokerova, D.: 1982, A method for compilation of seismic zoning prognostic maps for the territory of Bulgaria,Geologica Balcanica 12(2), 3?48.
5. Bonchev, Ek.: 1987, Main ideas in the tectonic synthesis of the Balkans. I. The lithospheric plates and the collision space between them,Geologica Balcanica 17(4), 9?20.