@article{1200692693,
author = {Yanagawa, Takaaki},
title = {On ribbon 2-knots. III. On the unknotting ribbon 2-knots in $S\sp4$},
journal = {Osaka J. Math.},
volume = {7},
number = {1},
year = {1970},
pages = { 165-172},
language = {en},
url = {http://dml.mathdoc.fr/item/1200692693}
}
Yanagawa, Takaaki. On ribbon 2-knots. III. On the unknotting ribbon 2-knots in $S\sp4$. Osaka J. Math., Tome 7 (1970) no. 1, pp. 165-172. http://gdmltest.u-ga.fr/item/1200692693/