“…In [12,17], H. Rosenberg and W. Meeks studied minimal surfaces in M 2 × R, where M 2 is a rounded sphere, a complete Riemannian surface with a metric of non-negative curvature, or M 2 = H 2 , the hyperbolic plane. Since then, there has been a rapid growing interest in minimal surfaces and surfaces with constant mean curvature in H 2 × R and S 2 × R, see for instance [4,5,9,13,14,15,18,19,20]. Also, surfaces in H 2 × R and S 2 × R with constant Gaussian curvature or constant extrinsic curvature have attracted many attention in the recent years, [1,2,3,6,7,16].…”