@article{JRAM_1996__479_153854,
     author = {Ulrike Tillmann},
     title = {The classifying space of the 1 + 1 dimensional cobordism category.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {67--76},
     publisher = {mathdoc},
     volume = {479},
     year = {1996},
     zbl = {0856.18010},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1996__479_153854/}
}