On the existence of two non-neighboring subgraphs in a graph. - Mohamed M. El-Zahar; Paul Erdös (Comb., 1985)

The chromatic number of the product of two 4-chromatic graphs is 4. - Mohamed M. El-Zahar; Norbert Sauer (Comb., 1985)

The indivisibility of the homogeneous Kn-free graphs. - Mohamed M. El-Zahar; Norbert Sauer (J. Comb. Theory B, 1989)

Ramsey-type properties of relational structures. - Mohamed M. El-Zahar; Norbert W. Sauer (Discret. Math., 1991)

On the Divisibility of Homogeneous Hypergraphs. - Mohamed M. El-Zahar; Norbert Sauer (Comb., 1994)

Indivisible homogeneous directed graphs and a game for vertex partitions. - Mohamed M. El-Zahar; Norbert Sauer (Discret. Math., 2005)