1. K.W. Wünschmann, (1905) Inaug. Dissert., Teubner, Leipzig, 1905.
2. La geometria de las ecuationes diferenciales de tercer orden;Cartan;Revista Mat. Hispano-Amer.,1940
3. Sur une classe d’espaces de Weyl;Cartan;Ann. Sci. Ecole Norm. Supp.,1943
4. Einstein–Weyl geometry, the dKP equation and twistor theory;Dunajski;J. Geom. Phys.,2001
5. E. Ferapontov, B. Kruglikov, Dispersionless integrable systems in 3D and Einstein–Weyl geometry, arXiv:1208.2728 (2012).