@article{10_4064_sm_51_3_251_263,
     author = {Bernard Morrel and Paul Muhly},
     title = {Centered operators},
     journal = {Studia Mathematica},
     pages = {251--263},
     publisher = {mathdoc},
     volume = {51},
     number = {3},
     year = {1974},
     doi = {10.4064/sm-51-3-251-263},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-51-3-251-263/}
}