1. P. R.Bishnoi PhD Thesis University of Alberta (Edmonton Canada)1970.
2. A. K.Mehrotra PhD Thesis University of Calgary (Calgary Canada)1980.
3. A.Vysniauskas PhD Thesis University of Calgary (Calgary Canada)1980.
4. H. C.Kim PhD Thesis University of Calgary (Calgary Canada)1985.
5. M. A.Trebble PhD Thesis University of Calgary (Calgary Canada)1986.