beta-Perfect Graphs. - S. E. Markossian; G. S. Gasparian; Bruce A. Reed (J. Comb. Theory B, 1996)

On essential components and critical sets of a graph. - S. E. Markossian; G. S. Gasparian; I. Karapetian; A. S. Markosian (Discret. Math., 1998)