@article{MZ_1964__86_170344,
     author = {Robert J. Koch},
     title = {Threads in compact semigroups.},
     journal = {Mathematische Zeitschrift},
     pages = {312--316},
     publisher = {mathdoc},
     volume = {86},
     year = {1964},
     zbl = {0126.26803},
     url = {http://geodesic.mathdoc.fr/item/MZ_1964__86_170344/}
}