@article{SF_1977__15_134235,
     author = {K. Todorov},
     title = {\"Uber einge {Eigenschaften} der {Kommutatoren} der symmetrischen {Halbgruppe.}},
     journal = {Semigroup forum},
     pages = {61--86},
     publisher = {mathdoc},
     volume = {15},
     year = {1977},
     zbl = {0375.20045},
     url = {http://geodesic.mathdoc.fr/item/SF_1977__15_134235/}
}