Hajo Broersma Ulrich Faigle Johann Hurink Stefan Pickl Gerhard J. Woeginger Preface: Volume 13. 128 2003 13 Electronic Notes in Discrete Mathematics http://dx.doi.org/10.1016/S1571-0653(05)80008-3 db/journals/endm/endm13.html#BroersmaFHPW03