Gevrey solvability and hypoellipticity of classes of partial differential operators
Solvability for a class of first order partial differential operators
Existence of periodic solutions for first-order partial differential equations
Solvability and hypoellipticity of first order partial differential operators and...
Solvability and hypoellipticity of first order partial differential operators and ...
Local solvability of rotationally invariant differential forms
Solvability for elliptic and canceling linear differential operators