Bruce, M.I., Ellis, B.G., Low, P.J., Skelton, B.W., White, A.H., "Syntheses, Structures, and Spectro-electrochemistry of Cp*(PP)RuC≡CC≡CRu(PP)Cp* (PP = dppm, dppe) and Their Mono- and Dications", Organometallics, 2003