References

Journal of Mathematical Sciences: Advances and Applications

WHEN ARE THE ZERO-ENERGY SOLUTIONS TO THE SCHRÖDINGER EQUATION BOUNDED AT INFINITY?

[1] A. G. Ramm, Sufficient conditions for zero not to be an eigenvalue of the Schrödinger operator, Journal of Mathematical Physics 28(6) (1987), 1341-1343.

[2] A. G. Ramm, Conditions for zero not to be an eigenvalue of the Schrödinger operator, II, Journal of Mathematical Physics 29(6) (1988), 1431-1432.