1. The role of difference equations, University of St. Androws preprint, 1964, unpublished.
2. Asymptotic expansions: their derivation and interpretation, Academic Press, London 1973.
3. and , ITEP (Moscow) preprint no. 101 (1982), unpublished.
4. Logarithmic perturbation theory for the screened Coulomb potential
5. Matching of WKB solutions to other solutions