@article{GDZPPN002061198,
title = {The Signature Defect and the Homotopy of BPL and PL/O},
journal = {Commentarii mathematici Helvetici},
volume = {48},
year = {1973},
pages = {525-530},
zbl = {0279.57012},
url = {http://dml.mathdoc.fr/item/GDZPPN002061198}
}
Frank, David. The Signature Defect and the Homotopy of BPL and PL/O. Commentarii mathematici Helvetici, Tome 48 (1973) pp. 525-530. http://gdmltest.u-ga.fr/item/GDZPPN002061198/