“…, z m ), with min 0 i m z i s. (H2) There is a rational function r(x) = −x/(1 + bx) with b > 0 such that r M(z) f n (z) r −M(−z) , n∈ Z + , (1.5) where the first inequality holds for all z ∈ R m+1 , and the second one for all z ∈ R m+1 such that min 0 i m z i > −b −1 ∈ (−∞, 0). To obtain sharp stability conditions, Tkachenko and Trofimchuk [11] restricted the range of parameter q, and for the sublinear case (b = 0), Nenya, Tkachenko and Trofimchuk [9] extended in the following range such that q + q 2 + · · · + q m q m+1 1.…”