1. Theoretical Kinematics;Bottema,1979
2. Kinematics of Spherical Mechanisms;Chiang,1988
3. Rational Kinematics;Angeles,1988
4. P. Larochelle, J. Dooley, P. Murray, M. McCarthy, SPHINX: Software for synthesizing spherical 4R mechanisms, in: Proceedings of the NSF Design and Manufacturing Systems Conference, University of North Carolina at Charlotte, NC, vol. 1, 1993, pp. 607–611.
5. The design of spherical 4R linkages for four specified orientations;Ruth;Mech. Mach. Theory,1999