@article{10_4064_fm_44_3_309_329,
     author = {A. Robinson},
     title = {Some problems of definability in the lower predicate calculus},
     journal = {Fundamenta Mathematicae},
     pages = {309--329},
     publisher = {mathdoc},
     volume = {44},
     number = {3},
     year = {1957},
     doi = {10.4064/fm-44-3-309-329},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-44-3-309-329/}
}