Geometric Integrability Theorems:
Jenssen, H. K. and Kogan, I. A.
A mixed boundary value problem for uxy=f(x,y,u,ux,uy).
The Journal of Differential Equations, 268 (12), (2020) 7535-7560.
ArXiv preprint
Benfield, M., Jenssen, H. K. and Kogan, I. A.
Jacobians with prescribed eigenvectors.
Journal of Differential Geometry and its Applications. Vol. 65, (2019), 108 - 146.
ArXiv preprint
Benfield, M., Jenssen, H. K. and Kogan, I. A.
A generalization of an integrability theorem of Darboux.
The Journal of Geometric Analysis, Vol. 29 No. 4 (2019), 3470 - 3493.
Benfield, M., Jenssen, H. K. and Kogan, I. A.
On two theorems of Darboux. (2017)