“…The condition 1/n + 1/d < 1 is equivalent to nd > m and this defines the set of values n, d ≥ 2 with m ≥ 5. The dynamics of some of these maps, the topological structures of their Julia sets and the structure of the parameter λ−planes have been widely studied by several authors, see for example [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]. A recent survey of results involving some of the maps in this family is given in [19].…”