@article{10_4153_CJM_1981_070_4,
     author = {Gerhard, J. A. and Petrich, Mario},
     title = {The {Word} {Problem} for {Orthogroups}},
     journal = {Canadian journal of mathematics},
     pages = {893--900},
     year = {1981},
     volume = {33},
     number = {4},
     doi = {10.4153/CJM-1981-070-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1981-070-4/}
}