[1] B. Ahmadi Kakavandi, Weak topologies in complete CAT(0) metric spaces, Proc. Amer. Math. Soc. 141 (2013), 1029–1039.
[2] B. Ahmadi Kakavandi and M. Amini, Duality and subdifferential for convex functions on complete CAT(0) metric spaces, Nonlinear Anal. 73 (2010), 3450–3455.
[3] M. Bacak, The proximal point algorithm in metric spaces, Isr. J. Math. 194 (2013), 689-701.
[4] M. Bacak, Convex Analysis and Optimization in Hadamard Spaces, De Gruyter Series in Nonlinear Analysis and Applications, 22. De Gruyter, Berlin, 2014.
[5] I.D. Berg and I.G. Nikolaev, Quasilinearization and curvature of Alexandrov spaces, Geom. Dedicata 133 (2008), 195-218.
[6] M. Bridson and A. Haefliger, Metric Spaces of Non-Positive Curvature, Vol. 319 SpringerVerlag, Berlin, Heidelberg, New York, 1999.
[7] D. Burago, Y. Burago and S. Ivanov, A Course in Metric Geometry, Graduate studies in Math., Vol. 33, Amer. Math. Soc., Providence, RI, 2001.
[8] H. Dehghan and J. Rooin, A characterization of metric projection in CAT(0) spaces, Int. Conf. Funct. Equ. Geo. Funct. Appl. Payame Noor University, Tabriz, 2012, pp. 41–43.
[9] M. Gromov and S.M. Bates, Metric structures for Riemannian and Non-Riemannian Spaces, Vol. 152, Boston: Birkhauser, 1999.
[10] M.T. Heydari and S. Ranjbar, Halpern-type proximal point algorithm in complete CAT(0) metric spaces, An. Stiint. Univ. Ovidius Constanta Ser. Mat. 24 (2016), 141–159.
[11] J. Jost, Nonpositive curvature: geometric and analytic aspects, Lectures in Mathematics, ETH Zurich. Basel: Birkhauser, 1997.
[12] S. Kamimura and W. Takahashi, Approximating solutions of maximal monotone operators in Hilbert spaces, J. App. Theory 106 (2000), 226–240.
[13] H. Khatibzadeh and S. Ranjbar, On the Hapern iteration in CAT(0) spaces, Ann. Funct. Anal. 6 (2015), 155165.
[14] H. Khatibzadeh and S. Ranjbar, A variational inequality in complete CAT(0) spaces, J. Fixed Point Theory Appl. 17 (2015), 557–574.
[15] H. Khatibzadeh and S. Ranjbar, Monotone operators and the proximal point algorithm in complete CAT(0) metric spaces, J. Aust. Math. Soc. 103 (2017), no. 1, 70–90.
[16] W.A. Kirk and B. Panyanak, A concept of convergence in geodesic spaces, Nonlinear Anal. 68 (2008), 3689–3696.
[17] C. Li, G. Lopez and V. Martın-Marquez, Monotone vector fields and the proximal point algorithm, J. London Math. Soc. 679 (2009), 663–683.
[18] T.C. Lim, Remarks on some fixed point theorems, Proc. Am. Math. Soc. 60 (1976), 179–182.
[19] B. Martinet, R´egularistion d’in´equations variationnelles par approximations successive, Rev. Francaise Inft. Recher op´erationnelle 4 (1970), 154–158.
[20] J.X. Da Cruz Neto, O.P. Ferreira, L.R. Lucambio Prez and S.Z. Nemeth, Convex and monotone transformable mathematical programming problems and a proximal-like point method, J. Global Optim. 35 (2006), no. 1, 53-–69.
[21] S. Ranjbar, W-convergence of the proximal point algorithm in complete CAT(0) metric spaces, Bull. Iran. Math. Soc. 43 (2017), 817–834.
[22] S. Ranjbar and H. Khatibzadeh, Strong and ∆-convergence to a zero of a monotone operator in CAT(0) spaces, Mediterr. J. Math. 14 (2017), no. 2, 1–15.
[23] T. Rockafellar, Monotone operators and the proximal point algorithm, SIAM J. Control Optim. 14 (1976), 79–83.
[24] W. Takahashi, Viscosity approximation methods for resolvents of accretive operators in Banach spaces, J. Fixed Point Theory Appl. 1 (2007), 135–147.
[25] S. Saejung and P. Yotkaew, Approximation of zeros of inverse strongly monotone operators in Banach spaces, Nonlinear Anal. 75 (2012), 742–750.