Grechneva, M. A., and P. G. Stegantseva. 2016. “On the Existence of a Surface in the Pseudo-Euclidean Space With Given Grassman Image”.
Ukrains’kyi Matematychnyi Zhurnal
68 (10): 1320=1329.
https://umj.imath.kiev.ua/index.php/umj/article/view/1923
.