1. Atkinson, F. V. “Limit-n criteria of integral type”, (to appear in Proc. Royal Soc. Edinburgh).
2. “Self-adjointness and spectra of Sturm-Liouville operators”;Brinck;Math. Scand.,1959
3. Brown, B. M, and Evans, W, D, “On the limit-point and strong limit-point classification of 2n order differential expressions with widely oscillating coefficients”, (to appear in Math. Zeit.).
4. Linear operators: Part II;Dunford,1963
5. “A note on the self-adjoint domains of second-order differential equations”;Everitt;Quart. J. Math. (Oxford),1963