Really Martin's commentcomment should be the answer, but note Wikipedia also gives:
Alexander Grothendieck, 1984. "Esquisse d'un Programme", (1984 manuscript), finally published in Schneps and Lochak (1997, I), pp.5-48; English transl., ibid., pp. 243-283.
and the latter reference is :
Schneps, Leila; Lochak, Pierre, eds. (1997), Geometric Galois Actions I: Around Grothendieck's Esquisse D'un ProgrammeGeometric Galois Actions I: Around Grothendieck's Esquisse D'un Programme, London Mathematical Society Lecture Note Series, 242, Cambridge University Press, ISBN 978-0-521-59642-8
(This even has a MR numberan MR number!)