1. Über nicht-Desarguessche Ebenen mit transitiver Translationsgruppe;André;Math. Z.,1954
2. Pascal's theorem on an oval;Artzy;Am. Math. Monthly,1968
3. F. Bachmann, 1971, Hjelmslev planes, Atti Convegno Geometria Combinatoria (Perugia), pp. 43-56.
4. Homogeneity of projective planes;Baer;Am. J. Math.,1942
5. Configurazioni k-chiuse e piani k-aperti;Barlotti;Rend. Sem. Mat. Padova,1965