For the paper Enhanced stiffness modeling of manipulators with passive joints
by A. Pashkevicha , A. Klimchik, D. Chablat
Submmited to "Mechanism and Machine Theory " (2010)
Buckling in S-configuration with 1D-springs (subsection 6.1.3)
Nonlinearity in ?-configuration with 1D-springs (subsection 6.1.3)
Buckling in Z-configuration with 1D-springs (subsection 6.1.3)
Buckling in manipulator with 3D-springs (subsection 6.1.5)
Buckling for near-flat configuration (subsection 6.2.4)