@article{MZ_1977__157_172597,
     author = {Donald J. Collins},
     title = {Generation and {Presentation} of {One-Relator} {Groups} with {Centre.}},
     journal = {Mathematische Zeitschrift},
     pages = {63--78},
     publisher = {mathdoc},
     volume = {157},
     year = {1977},
     zbl = {0348.20030},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__157_172597/}
}