1. Δu = eu und die automorphen Funktionen;Bieberbach;Math. Annln,1916
2. Einige besondere probleme partieller Differentialgleichungen;Rademacher,1943
3. On solutions of Δu = f(u);Keller;Communs pure appl. Math.,1957
4. Partial differential equations invariant under conformal or projective transformations;Loewner,1974
5. The Dirichlet problem for the equation Δu = u2;Pohozaev;Dokl. Akad. Nauk. SSSR,1960