@article{10_4153_CJM_1988_004_3,
     author = {Powers, Robert T.},
     title = {An {Index} {Theory} for {Semigroups} of {*-Endomorphisms} of and {Type} {II1} {Factors.}},
     journal = {Canadian journal of mathematics},
     pages = {86--114},
     year = {1988},
     volume = {40},
     number = {1},
     doi = {10.4153/CJM-1988-004-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1988-004-3/}
}