@article{AMLG_1977__18_137934,
     author = {J.A. Makowsky and S. Tulipani},
     title = {Some model theory for monotone quantifiers.},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {115--134},
     publisher = {mathdoc},
     volume = {18},
     year = {1977},
     zbl = {0365.02042},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1977__18_137934/}
}