Christian Bessière Arnold Maestre Ismel Brito Pedro Meseguer Asynchronous backtracking without adding links: a new member in the ABT family. 7-24 2005 161 Artif. Intell. 1-2 http://dx.doi.org/10.1016/j.artint.2004.10.002 db/journals/ai/ai161.html#BessiereMBM05