Rozenblum, Grigori, and Nikolay Shirokov. “Entire Functions in Weighted 𝘓₂ and Zero Modes of the Pauli Operator With Non-Signdefinite Magnetic Field”. CUBO, A Mathematical Journal, vol. 12, no. 1, Mar. 2010, pp. 115–132, doi:10.4067/S0719-06462010000100011.