1. Köster, W.; Horn, E. (Z. Metallic. 43 [1952] 444/9).
2. Ellison, K.A.; Underhill, P.R.; Smeltzer, W.W. (Surf. Sci. 182 [1987] 69/84).
3. Handley, J.R. (Platinum Metals Rev. 33 [1989] 64/72).
4. Mit’ko, M.M.; Dubinin, E.L.; Chegodaev, A.I. (Soviet Non-Ferrous Metals Res. 6 [1978] 115/7).
5. Crangle, J.; Parsons, D. (Proc. Roy. Soc. [London] A255 [1960] 509/19).