Luca Aceto Mario Bravetti Wan Fokkink Andrew D. Gordon Guest Editors' Foreword. 119-120 2007 70 J. Log. Algebr. Program. 2 http://dx.doi.org/10.1016/j.jlap.2006.08.002 db/journals/jlp/jlp70.html#AcetoBFG07