@article{ZNSL_1996_232_a6,
     author = {B. Gustafsson and D. Khavinson},
     title = {On annihilators of harmonic vector fields},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {90--108},
     year = {1996},
     volume = {232},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1996_232_a6/}
}