Two sets of graceful graphs
Charles Delorme · Journal of Graph Theory · 1980
Abstract We give graceful numberings to the following graphs: (a) the union of n K4 having one edge in common, in other words the join of K2 and the union of n disjoint K2 and (b) the union of n C4 having one edge in common, in other words the product of K2 and K1,n, with n + 1 not a multiple of 4.