@article{10_4153_CJM_1988_043_5,
     author = {Ryshkov, S. S. and Erdahl, R. M.},
     title = {The {Empty} {Sphere} {Part} {II}},
     journal = {Canadian journal of mathematics},
     pages = {1058--1073},
     year = {1988},
     volume = {40},
     number = {5},
     doi = {10.4153/CJM-1988-043-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1988-043-5/}
}