A panel of peralkylated sulfur–guanidine type bases: Novel pro-ligands for use in biomimetic coordination chemistry
A. Neuba, M. Rohrmüller, R. Hölscher, W.G. Schmidt, G. Henkel, Inorganica Chimica Acta 430 (2015) 225–238.

Highly flexible O,O,N ligands and their Fe, Ni, Cu and Zn complexes
K. Butsch, A. Klein, M. Bauer, Inorganica Chimica Acta 374 (2011) 350–358.

From the Cu(;c2-S)N4 butterfly architecture to the Cu(;c3-S)N12 double wheel
M.S. Ameerunisha Begum, O. Seewald, U. Flörke, G. Henkel, Inorganica Chimica Acta 361 (2008) 1868–1874.