[1] Hamann U.: Eigenschaften von Potentialen bezüglich elliptischer Differentialoperatoren. Math. Nachr. 96 (1980), 7-15. MR 0600795 | Zbl 0456.31008

[2] Harvey Polking: Removable singularities of solutions of linear partial differential equations. Acta Mathematica 125 (1970), 39-56. MR 0279461

[3] Král J.: Hölder-continuous heat potentials. Accad. Naz. Lincei, Rendiconti Cl. Sc. fis., mat. Ser. VIII (1971), vol. LI, 17-19. MR 0308593