@article{JCEM_2015_2_4_a8,
     author = {O. A. Torshina},
     title = {Differential operators on the projective plane},
     journal = {Journal of computational and engineering mathematics},
     pages = {84--94},
     publisher = {mathdoc},
     volume = {2},
     number = {4},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JCEM_2015_2_4_a8/}
}