Abstract: In this paper, we prove We also establish characterizations
of graphs whose products have crossing number 1. In addition, we present a
necessary and sufficient condition for the graphs whose product is minimally
nonouterplanar. Finally we obtain a necessary and sufficient condition for the
graphs whose product is minimally nonouterplanar in terms of forbidden subgraphs.
Keywords and phrases: product of graphs, minimally nonouterplanar graph, crossing number.
