Աղավարդ Խաչատրյան

 International conference on ,,Numerical methods", ESTONIA, 1988. 
 Astrophysics seminar of Arvine University California, USA, 1992. 
 International conference dedicated to 50-th anniversary of Byurakan Astrophysical Observatory , 1996 
 International conference of Mathematician (ISAAC), Yerevan, 2002