1. For a recent review see;Cowley;Polyhedron,1984
2. Dissertation Universitdt Konstanz Unconventional multiple bonds;Lang;Naturforsch b,1985
3. in press;Sigwarth;Chem Ber
4. in press;Lang;Organomet Chem
5. Similar trapping experiments have also been done by and Sulfur For an explanation in terms of electron repulsions see;Mathey;Organometallics Huttner Chem Angew Chem mt Engi Organomet Chem,1983