J. F. Berry, Multiple Bonds between Metal Atoms, pp.669-706, 2005.

M. M. Warnke, F. A. Cotton, and D. W. Armstrong, Chirality, vol.19, p.179, 2007.

A. Srinivasan, M. Cortijo, V. Bulicanu, A. Naim, R. Clérac et al., Chem. Sci, vol.9, p.1136, 2018.

, cobalt (dark blue), nitrogen (pale blue), chloride (green). (Right) Helicoidal wrapping of dpa ligand