A graph G with q edges is said to be harmonious, if there is an injection f from the vertices of G to the group of integers modulo q such that when each edge xy is assigned the label f(x)+f(y) (mod q), the resulting edge labels are distinct. In this paper, we study the existence of harmonious labeling for the corona graphs of a cycle and a graph G and for the corona graph of K2 and a tree

Maged Z. Youssef