1. Baird, P., Bejan, C.L.: Quasi-harmonic maps between almost symplectic manifolds. Harmonic maps, harmonic morphisms and related topics, Brest 1997, Chapman and Hall/CRC Research Notes in Mathematics, vol. 413, pp. 75–95 (2000)
2. Baird, P., Wood, J.C.: Harmonic morphisms between Riemannian manifolds. London Mathematical Society Monograph (New Series). Oxford University Press, New York (2003)
3. Bejan, C.L.: A classification of the almost para-Hermitian manifolds. In: Differential Geometry and its applications Dubrovnik 1988, University of Novi Sad, pp. 23–27 (1989)
4. Bejan, C.L.: Some examples of manifolds with hyperbolic structures. Rend. Mat. Appl. (7) 14(4), 557–565 (1994)
5. Bejan C.L.: Quasi-harmonic morphisms. Ital. J. Pure Appl. Math. 18, 51–68 (2005)