@article{SF_1972__4_133883,
     author = {W.R. Nico},
     title = {A counterexample in the cohomology of monoids.},
     journal = {Semigroup forum},
     pages = {93--94},
     year = {1972},
     volume = {4},
     zbl = {0254.18011},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__4_133883/}
}