@article{10_1017_S0017089500004560,
     author = {Carvalho, F. J.Craveiro de},
     title = {Immersed surfaces and pencils of planes in 3-space},
     journal = {Glasgow mathematical journal},
     pages = {133--136},
     year = {1981},
     volume = {22},
     number = {2},
     doi = {10.1017/S0017089500004560},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500004560/}
}