Dolgii, Shapiro, Nefedov Bull. of the Acad. of Sc. USSR 1975, 24:1569.
Hubert, Noels, Anciaux, Teyssié (1976) Rhodium(II) Carboxylates: Novel Highly Efficient Catalysts for the Cyclopropanation of Alkenes with Alkyl Diazoacetates. Synthesis , and references therein; 600.