Paris, PUF, coll. Que sais-je ? 2014, ISBN-978-2-13-063490-4, 127 p.
P.U.F. - Paris - 1992 - 296 p.
Volume V of the Santa Fé Institute Studies in the Sciences of Complexity, AddisonWesley Pub. Cy. N.Y. 1988. 317 p.