@article{ASNSP_1975_4_2_4_557_0,
     author = {Stormark, Olle},
     title = {A note on a paper by {Andreotti} and {Hill} concerning the {Hans} {Lewy} problem},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {557--569},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 2},
     number = {4},
     year = {1975},
     mrnumber = {477151},
     zbl = {0313.32019},
     language = {en},
     url = {http://archive.numdam.org/item/ASNSP_1975_4_2_4_557_0/}
}