@article{10_2140_agt_2007_7_1379,
     author = {Fischer, Hanspeter},
     title = {Pullbacks of generalized universal coverings},
     journal = {Algebraic and Geometric Topology},
     pages = {1379--1388},
     year = {2007},
     volume = {7},
     number = {3},
     doi = {10.2140/agt.2007.7.1379},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2007.7.1379/}
}