// <I>Physics and Chemistry<D>: Anniversary Scientific Conference "25 Years of Shoumen Univ. "Bishop K. Preslavsky", Shumen, 1999: Proc.- Shumen, 1999, p. 21-24.
(1999)
G. Krumova; M. Gaidarov; S. Dimitrova;
A. Antonov;
M. Stoitsov;
P. Hodgson;
V. Lukyanov;
E. Zemlyanaya и др.