“…Both concepts generalize in a natural way those classical ones concerning the proper coloring and the chromatic number of a graph, which arise indeed when r = 1. Since the original work of Montgomery, the case r > 1 has widely been dealt with in the literature for different types of graphs [8,6,7,11,12,14,15,19,22,24], with particular emphasis in the case r = 2 [1,2,3,4,5]. Of particular interest for the topic of this paper, let us remark the studies of Mohanapriya et al [20] and Furmańczyk et al [9] concerning the r-dynamic coloring of different families of helm graphs.…”