The notion of an elementary subsystem for a Boolean-valued relational system L. Szczerba — 1973 Fundamenta Mathematicae
Errata to the paper "Relations on lines as primitive notions for Euclidean geometry", Fundamenta Mathematicae 82 (1975), pp. 347-355 W. Schwabhäuser; L. Szczerba — 1975 Fundamenta Mathematicae
Relations on lines as primitive notions for Euclidean geometry W. Schwabhäuser; L. Szczerba — 1975 Fundamenta Mathematicae
Metamathematical discussion of some affine geometries L. Szczerba; Alfred Tarski — 1979 Fundamenta Mathematicae