“…The same result for outerplanar graphs was obtained by Hou et al [14]. Wang et al [17,19] proved that every planar graph G has a (G) = if there is a pair (k, g) ∈ { (3,11), (4,8), (5,7), (8,6), (12,5)} such that G satisfies ≥ k and g(G) ≥ g, and Hudák et al [12] proved that every planar graph G has a (G) = if g ≥ 12 or there is a pair (k, g) ∈ { (4,8), (5,7), (6,6), (10,5)} such that G satisfies ≥ k and g(G) ≥ g, independently. Dong and Xu [9] proved that if G is a planar graph with g(G) ≥ 4, then a (G) ≤ + 5.…”