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• [1] Alexander, S., Local and global convexity in complete Riemannian manifolds. Pacific Journal of Mathematics 76(1978), no. 2 , 283-289.
• [2] Balashov, M. V., An Analog of the Krein-Mil’man Theorem for Strongly Convex Hulls in Hilbert Space. Mathematical Notes 71(2002), no. 1-2 , 34-38.
• [3] Beltagy, M., Sufficient conditions for convexity in manifolds without focal points. Comment. Math. Univ. Carolinae 34 (1993), 443-449.
• [4] Beltagy, M., Local and global exposed points. Acta Mathematica Scientia 15(1995), no. 3 , 335-341.
• [5] Beltagy, M., On starshaped sets. Bull. Malays. Math. Soc., II. Ser. 11(1988), no. 2 , 49–57.
• [6] Burns, K., The flat strip theorem fails for surfaces with no conjugate points. Proceedings of the American Mathematical Society 115(1992), no. 1, 199-206.
• [7] Eberlein, P., Geodesic flow in certain manifolds without conjugate points. Transactions of the American Mathematical Society 167 (1972), 151-170.
• [8] Emmerich, P., Rigidity of complete Riemannian manifolds without conjugate points. Shaker Verlag Gmbh, Germa, 2013.
• [9] Green, L. W., Surfaces without conjugate points. Transactions of the American Mathematical Society 76(1954), no. 3 , 529-546.
• [10] Goto, M. S., Manifolds without focal points. Journal of Differential Geometry 13(1978), no. 3 , 341-359.
• [11] Gulliver, R., On the variety of manifolds without conjugate points. Transactions of the American Mathematical Society 210 (1975), 185-201.
• [12] Ivanov, S. and Vitali K. Manifolds without conjugate points and their fundamental groups. Journal of Differential Geometry 96(2014), no. 2 , 223-240.
• [13] Jaume, D. A. and Rubén, P., Conjugacy for closed convex sets. Contributions to Algebra and Geometry 46 (2005), no. 1, 131-149.
• [14] Lay, S.R., Convex sets and their applications. Courier Corporation, 2007.
• [15] Li, S. and Yicheng G., On the relations of a convex set and its profile. In Integral Geometry and Convexity pp. 199-211. 2006.