@article{10_4153_CJM_1966_028_9,
     author = {Lappan, P. and Rung, D. C.},
     title = {Normal {Functions} and {Non-Tangential} {Boundary} {Arcs}},
     journal = {Canadian journal of mathematics},
     pages = {256--264},
     year = {1966},
     volume = {18},
     number = {1},
     doi = {10.4153/CJM-1966-028-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1966-028-9/}
}