@article{SF_1972__5_133931,
     author = {W.R. Nico},
     title = {Some finiteness conditions on indecomposable operands.},
     journal = {Semigroup forum},
     pages = {145--153},
     publisher = {mathdoc},
     volume = {5},
     year = {1972},
     zbl = {0264.20048},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__5_133931/}
}