@article{SF_1986__33_134804,
     author = {T. Harju and J. Karhum\"aki},
     title = {On the defect theorem and simpliflability.},
     journal = {Semigroup forum},
     pages = {199--218},
     publisher = {mathdoc},
     volume = {33},
     year = {1986},
     zbl = {0621.20033},
     url = {http://geodesic.mathdoc.fr/item/SF_1986__33_134804/}
}