@article{GDZPPN002068397,
title = {Extending immersed circles in the sphere to immersed disks in the ball.},
journal = {Commentarii mathematici Helvetici},
volume = {67},
year = {1992},
pages = {337-348},
zbl = {0766.57018},
url = {http://dml.mathdoc.fr/item/GDZPPN002068397}
}
Carter, J. Scott. Extending immersed circles in the sphere to immersed disks in the ball.. Commentarii mathematici Helvetici, Tome 67 (1992) pp. 337-348. http://gdmltest.u-ga.fr/item/GDZPPN002068397/