@article{DOCMA_2014__19__a10,
     author = {Hajac, Piotr M. and Wagner, Elmar},
     title = {The pullbacks of principal coactions},
     journal = {Documenta mathematica},
     pages = {1025--1060},
     publisher = {mathdoc},
     volume = {19},
     year = {2014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DOCMA_2014__19__a10/}
}