Gruson, Laurent (1992), "Un aperçu des travaux mathématiques de G.H. Halphen (1844-1889)" [An overview of the mathematical work of G.H. Halphen (1844-1889)], in Ellingsrud, G.; Peskine, C.; Stromme, S.A. (eds.), Complex Projective Geometry, London Math. Soc. Lecture Note Series (in French), vol. 179, pp. 189–198, doi:10.1017/CBO9780511662652.014, ISBN9780521433525