1981
E. A. Varbanova
Sofia University · Moscow State
1984
Svetozar Margenov
Institute of Mathematics, BAS
1985
Andrey Andreev
Institute of Mathematics, BAS
1985
Mohamed El Hatri
Sofia University
1988
Lyuben Vulkov
Institute of Mathematics, BAS
1989
Atanas Pehlivanov
Sofia University
1991
N. Kumanov
Institute of Mathematics, BAS
1993
S. Petrova
Sofia University
1996
Ilia Michev
Texas A&M University
1996
Serguei Maliassov
Texas A&M University
1999
S. Fidanova
Sofia University
1999
T. Dimov
Institute of Mathematics, BAS
1999
Vesselin Kantchev
Institute of Mathematics, BAS
1999
Hong Huang
Texas A&M University
2002
S. Tomov
Texas A&M University
2004
Victor Ginting
Texas A&M University
—
V. Dobrev
Texas A&M University
—
S. Ki Kang
Texas A&M University
—
Y. Mao
Texas A&M University
—
M. Moon
Texas A&M University
—
Zhi Zhou
Texas A&M University · with B. Jin