@article{SF_1984__29_134689,
     author = {N. Kehayopulu},
     title = {On regular and intra-regular poe semigroups.},
     journal = {Semigroup forum},
     pages = {255--257},
     publisher = {mathdoc},
     volume = {29},
     year = {1984},
     zbl = {0537.06013},
     url = {http://geodesic.mathdoc.fr/item/SF_1984__29_134689/}
}