by GEORGIEV, MARIN Z, KHRUSANOV, VASKO G, MARTINOV, PAVEL M, STOJCHEV, STEFKO D, TODOROV, ASEN N, DANCHEV, DANCHO I
Year of Publication 15.07.1991

by PETROV,PETR T, AVRAMOV,MISHEL L, BOROVSKI,BORIS KH, MARTINOV,PAVEL M, TODOROV,ASEN N, MONCHEV,PETKO M
Year of Publication 16.01.1984

by METEV, GEORGI M, MARTINOV, PAVEL M, RASHKOVA, RADKA K, MILCHEVA, NADKA M, TODOROV, ASEN N
Year of Publication 27.02.1998