1. Trimm, D.L., next chapter in this volume, Table 1 (taken with permission from C.A.Bernardo, ref. 16)
2. Presland, A.E.B., P.L.Walker Jr., Carbon, 7, 1 (1969)
3. Robertson, S.D., Carbon, 8, 365 (1970)
4. Tesner, P.A., E.Y. Robinovich, I.S. Rafalkes, E.F. Arefieva, Carbon, 8, 435 (1970)
5. Renshaw, G.D., C.Roscoe, P.L.Walker Jr., J.Catal., 22, 394 (1971)