D. Calderbank, M. Eastwood, V. S. Matveev, and K. Neusser, C-Projective Geometry: Background and Open Problems, in preparation.
M. Eastwood and V. S. Matveev, “Metric connections in projective differential geometry,” in: M. Eastwood and W. Miller, eds., Symmetries and Overdetermined Systems of Partial Differential Equations, IMA Vol. Math. Appl., Vol. 144, Springer, New York (2007), pp. 339–351.
V. Kiosak and V. S. Matveev, “Proof of the projective Lichnerowicz conjecture for pseudo-Riemannian metrics with degree of mobility greater than two,” Commun. Math. Phys., 297, No. 2, 401–426 (2010).
K. Kiyohara, “Compact Liouville surfaces,” J. Math. Soc. Jpn., 43, 555–591 (1991).
T. Levi-Civita, “Sulle trasformazioni delle equazioni dinamiche,” Ann. Mat. Pura Appl. (1867–1897 ), 24, No. 1, 255–300 (1896).
V. S. Matveev, “Beltrami problem, Lichnerowicz–Obata conjecture and applications of integrable systems in differential geometry,” Tr. Sem. Vektorn. Tenzorn. Anal., 26, 214–238 (2005).
V. S. Matveev, “On degree of mobility for complete metrics,” Adv. Stud. Pure Math., 43, 221–250 (2006).
V. S. Matveev, “Three-dimensional manifolds having metrics with the same geodesics,” Topology, 42, No. 6, 1371–1395 (2003).
V. S. Matveev, “Proof of projective Lichnerowicz–Obata conjecture,” J. Differ. Geom., 75, 459–502 (2007).
V. S. Matveev and P. Mounoud, “Gallot–Tanno theorem for closed incomplete pseudo-Riemannian manifolds and applications,” Ann. Glob. Anal. Geom., 38, 259–271 (2010).
A. Zeghib, On Discrete Projective Transformation Groups of Riemannian Manifolds, arXiv:1304.6812v1.