Originally published by:
Van Nostrand Reinhold, 1971
Keywords: groupoids, subgroup theorems, covering morphisms, fundamental group, homology of groupoids
2000 MSC: 20L05, 18-01, 20E07, 20J05, 18B40, 18G30, 55Q05
Republished in:
Reprints in Theory and Applications of Categories,
No. 7 (2005) pp 1-195
http://www.tac.mta.ca/tac/reprints/articles/7/tr7.pdf
Additional page set-ups - see
Notes on Printing.
http://www.tac.mta.ca/tac/reprints/articles/7/tr7-2a4.pdf
http://www.tac.mta.ca/tac/reprints/articles/7/tr7-2l.pdf