1. Entrelacements et équations de Pfaff;Bennequin;Astérisque,1983
2. S. Chmutov, V. Goryunov, Knot polynomials and invariants of Legendrian knots, in: Topics in Singularity Series, AMS Translations, Ser. 2, Vol. 180, 1997, pp. 25–43.
3. Yu. Chekanov, Differential algebras of Legendrian links, Fields Institute Preprint, 1997; Corrected Version, 1999.
4. Ya. Eliashberg, Invariants in contact topology, in: Proceedings of the International Congress on Mathematics, Vol. II, Document on Mathematics, 1998, Extra Vol. II, pp. 327–338 (electronic).
5. Ya. Eliashberg, M. Fraser, Classification of topologically trivial Legendrian knots, Geometry, Topology, Dynamics (Montreal, PQ, 1995), CRM Proceedings, Lecture Notes, Vol. 15, AMS, 1998, pp. 17–51.