[1] Kechichian, J. A., "Optimal low-thrust transfer using variable bounded thrust", Acta Astronautica, Vol. 36, No. 7, pp. 357-365, 1995.
[2] Guelman, M., "Earth to Moon transfer with a limited power engine", American Institute of Aeronautics and Astronautics, AIAA/AAS Astrodynamics Specialist Conference, Scottsdale, Arizona, 1994.
[3] Guelman, M. "Earth to Moon transfer with a limited power engine", Journal of Guidance, Control and Dynamics, Vol.18, No 5, pp. 1133–1138, 1995.
[4] Oberle, H. J. and Taubert, K., "Existence and multiple solutions of the minimum-fuel orbit transfer problem", Journal of Optimization Theory and Applications, Vol. 95, No 2, pp. 243–262, 1997.
[5] Nah, R. S. and Vadali, S. R., "Fuel-optimal low-thrust three-dimensional Earth-Mars trajectories", Journal of Guidance, Control, and Dynamics, Vol. 24, No. 6, pp. 1100–1107, 2001.
[6] Colasurdo, G. and Casalino, L. "Optimal low-thrust maneuvers in presence of Earth shadow", American Institute of Aeronautics and Astronautics, AIAA/AAS Astrodynamics Specialist Conference and Exhibit, Rhode Island, 2004.
[7] Pourtakdoust, S. H. and Jalali, M. A., "Thrust Limited Optimal Three Dimensional Spacecraft Trajectories", International Journal of Engineering, Vol.14, No. 1, pp. 81-90.
[8] Betts, J. T., "Using sparse nonlinear programming to compute low thrust orbit transfers", The Journal of the Astronautical Sciences, Vo. 41, pp. 349-371, 1993.
[9] Betts, J. T., "Survey of numerical methods for trajectory optimization", Journal of Guidance, Control, and Dynamics, Vol. 21, pp. 193-207, 1998.
[10] Betts, J. T., "Very low thrust trajectory optimization", in High Performance Scientific and Engineering Computing, Proceedings of the International FORTWIHR Conference on HPSEC, Munich, 1998.
[11] Betts, J. T., "Very low thrust trajectory optimization using a direct SQP method", Journal of Computational and Applied Mathematics, 120, pp. 27-40, 2000.
[12] Zondervan, K. P., Wood, L. J. and Caughey, T. K., "Optimal low-thrust, three-burn orbit transfers with large plane changes", The Journal of the Astronautical Sciences, Vol. 32, No.4, pp. 407–428, 1984.
[13] Kluever, C. A. and Pierson, B. L., "Optimal low-thrust Earth-Moon transfers with a switching function", The Journal of the Astronautical Sciences, Vol. 42, No. 3, pp. 269–284, 1994.
[14] Schoenmaekers, J. ,Horas, D. and Pulido, J. A., "SMART-1 with solar electric propulsion to the Moon", In Proceedings of the 16th International Symposium on Space Flight Dynamics, California, pp. 114-120, 2001.
[15] Walker, M., Ireland, B. and Owens, J., "A set of modified equinoctial orbit elements", Journal of Celestial Mechanics, Vol. 36, pp. 409-419, 1985.
[16] Betts, J. T., "Survey of numerical methods for trajectory optimization", Journal of Guidance, Control, and Dynamics, Vol. 21, No.2, pp. 193–207, 1998.
[17] Betts, J. T., "Practical methods for optimal control using nonlinear programming", Society for Industrial and Applied Mathematics, 2001.
[18] VonStryk, O. and Bulirsch, R., "Direct and indirect methods for trajectory optimization", Annals of Opera-tions Research, Vol. 37, pp. 357-373, 1992.
[19] Wächter, A., Introduction to IPOPT, Carnegie Mellon University, 2008.
[20] Wächter, A. and Biegler, L. T., "On the implement-ation of an interior-point filter line-search algorithm for large-scale nonlinear programming", Journal of Mathematical Programming, Vol. 106, No. 1, pp. 25–57, 2006.
[21] Wächter, A., An interior point algorithm for large scale nonlinear optimization with applications in process engineering, PhD thesis, Carnegie Mellon University, Pennsylvania, 2002.