1. Levin B, Kheyfits A: Asymptotic behavior of subfunctions of time-independent Schrödinger operator. In Some Topics on Value Distribution and Differentiability in Complex and P-Adic Analysis. Science Press, Beijing; 2008:323–397. chap. 11
2. Gilbarg D, Trudinger NS: Elliptic Partial Differential Equations of Second Order. Springer, Berlin; 1977.
3. Courant R, Hilbert D 1. In Methods of Mathematical Physics. Interscience, New York; 2008.
4. Verzhbinskii GM, Maz’ya VG: Asymptotic behavior of solutions of elliptic equations of the second order close to a boundary. I. Sib. Math. J. 1971, 12: 874–899.
5. Long PH, Gao ZQ, Deng GT: Criteria of Wiener type for minimally thin sets and rarefied sets associated with the stationary Schrödinger operator in a cone. Abstr. Appl. Anal. 2012., 2012: Article ID 453891