On Certain Maximal Subgroups of Symmetric or Alternating Groups. Emmanuel Halberstadt — 1976 Mathematische Zeitschrift
On the modular curve X ndép ( 11 ) . (Sur la courbe modulaire X ndép ( 11 ) .) Halberstadt, Emmanuel — 1998 Experimental Mathematics
On the modular curve X E ( 7 ) . (Sur la courbe modulaire X E ( 7 ) .) Halberstadt, Emmanuel; Kraus, Alain — 2003 Experimental Mathematics