@article{FassbenderVogler2008,
  author    = {Heinz Faßbender and Heiko Vogler},
  title     = {A universal unification algorithm based on unification-driven leftmost outermost narrowing},
  journal   = {Acta Cybernetica. 11 (1994), H. 3},
  pages     = {139 -- 167},
  year      = {2008},
}