@article{GDZPPN002062984,
title = {Quadruple points of 3-manifolds in S4.},
journal = {Commentarii mathematici Helvetici},
volume = {53},
year = {1978},
pages = {385-394},
zbl = {0404.57011},
url = {http://dml.mathdoc.fr/item/GDZPPN002062984}
}
Freedman, Michael H. Quadruple points of 3-manifolds in S4.. Commentarii mathematici Helvetici, Tome 53 (1978) pp. 385-394. http://gdmltest.u-ga.fr/item/GDZPPN002062984/