@article{GDZPPN002064391,
title = {Aspherical four-manifolds and the centres of two-knot groups.},
journal = {Commentarii mathematici Helvetici},
volume = {56},
year = {1981},
pages = {465-473},
zbl = {0478.57016},
url = {http://dml.mathdoc.fr/item/GDZPPN002064391}
}
Hillman, Jonathan A. Aspherical four-manifolds and the centres of two-knot groups.. Commentarii mathematici Helvetici, Tome 56 (1981) pp. 465-473. http://gdmltest.u-ga.fr/item/GDZPPN002064391/