@article{vanLeeuwen:1978,
    Address = {Amsterdam, The Netherlands, The Netherlands},
    Author = {van Leeuwen, Jan},
    File = {Effective Constructions in Well-partially- Ordered Free Monoids - Leeuwen (1) (0) - a - a - i.pdf},
    ISSN = {0012-365X},
    Journal = {Discrete Math.},
    Month = {May},
    Number = {3},
    Pages = {237--252},
    Publisher = {Elsevier Science Publishers B. V.},
    Title = {Effective Constructions in Well-partially- Ordered Free Monoids},
    URL = {http://dx.doi.org/10.1016/0012-365X(78)90156-5},
    Volume = {21},
    Year = {1978},
    acmid = {2784451},
    bdsk-url-1 = {http://dx.doi.org/10.1016/0012-365X(78)90156-5},
    date-added = {2016-01-13 15:47:49 +0000},
    date-modified = {2016-01-13 15:49:24 +0000},
    issue_date = {May 1978},
    numpages = {16},
    doi = {10.1016/0012-365X(78)90156-5}
}

@article{vanLeeuwen:1978, Address = {Amsterdam, The Netherlands, The Netherlands}, Author = {van Leeuwen, Jan}, File = {Effective Constructions in Well-partially- Ordered Free Monoids - Leeuwen (1) (0) - a - a - i.pdf}, ISSN = {0012-365X}, Journal = {Discrete Math.}, Month = {May}, Number = {3}, Pages = {237--252}, Publisher = {Elsevier Science Publishers B. V.}, Title = {Effective Constructions in Well-partially- Ordered Free Monoids}, URL = {http://dx.doi.org/10.1016/0012-365X(78)90156-5}, Volume = {21}, Year = {1978}, acmid = {2784451}, bdsk-url-1 = {http://dx.doi.org/10.1016/0012-365X(78)90156-5}, date-added = {2016-01-13 15:47:49 +0000}, date-modified = {2016-01-13 15:49:24 +0000}, issue_date = {May 1978}, numpages = {16}, doi = {10.1016/0012-365X(78)90156-5} }