@article{AMLG_1981__21_137973,
     author = {S. Shelah and J.A. Makowsky},
     title = {The theorems of {Beth} and {Craig} in abstract model theory. {II.} {Compact} logics.},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {13--36},
     publisher = {mathdoc},
     volume = {21},
     year = {1981},
     zbl = {0472.03028},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1981__21_137973/}
}