1. R.L. Jacobson, M.E. Kluksdahl and L.S. McCoy, API Proc. Div. of Refining 49 (1969) 504.
2. K.W. McHenry Jr., R.J. Bertolacini, H.M. Brennan, J.L. Wilson and H.S. Seelig,Actes 2nd Congr. Int. Catal, 1960, Vol. 2 (1961) p. 2293.
3. W.N. Lyster, dissertation, University of Houston, USA (1964).
4. A.G. Goble and P.A. Lawrence,Proc. 3rd Int. Congr. on Catalysts, Vol.1 (North-Holland, Amsterdam, 1965)p. 321.
5. N.R. Bursain, S.B. Kogan and Z.A. Davydova, Kinet. Katal. 6 (1965) 1046.