@article{10_4064_fm_84_1_75_78,
     author = {Hartmut H\"opft},
     title = {A normal form for some semigroups generated by idempotents},
     journal = {Fundamenta Mathematicae},
     pages = {75--78},
     publisher = {mathdoc},
     volume = {84},
     number = {1},
     year = {1974},
     doi = {10.4064/fm-84-1-75-78},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-84-1-75-78/}
}