“…The first one is known as the second Hankel determinant and it was examined in many papers. The investigation of Hankel determinants for analytic functions was started by Pommerenke (see [11,12]). Following Pommerenke, many mathematicians published their results concerning the second Hankel determinant for various classes of univalent functions (see, for example, [2,3,5,8,10]) or multivalent functions (see [9]).…”