1. Electromagnetic Diffraction and Propagation Problems;Fock,1965
2. On application of the parabolic equation method to wave field calculation in an inhomogeneous ionosphere;Cherkashin,1977
3. Calculation of wave fields in smoothly non-uniform media by means of the parabolic equation method;Cherkashin,1980
4. Numerical Methods;Samarsky,1989