ed. by M. Borissov.International School on Condensed Matter Physics (2nd : 1982 : Varna):Optical and acoustic waves in solids-modern topics, proceedings of the 2nd International School on Condensed Matter Physics.World Scientific,1983.
International School on Condensed Matter Physics (2nd : 1982 : Varna):Optical and acoustic waves in solids-modern topics, proceedings of the 2nd International School on Condensed Matter Physics
ed. by I. J. Lalev.International School on Condensed Matter Physics (1st : 1980 : Varna, Bulgaria):Modern problems of surface physics ; ISCMP ; Lectures.Bulgarian Academy of Sciences,1981.