@article{SF_1986__33_134819,
     author = {J. Almeida},
     title = {Power pseudovarieties of semigroups {I.}},
     journal = {Semigroup forum},
     pages = {357--374},
     publisher = {mathdoc},
     volume = {33},
     year = {1986},
     zbl = {0588.20033},
     url = {http://geodesic.mathdoc.fr/item/SF_1986__33_134819/}
}