@inproceedings{Beckert94a,
author = {Bernhard Beckert},
title = {A Completion-Based Method for Mixed Universal and
Rigid {$E$}-Unification},
booktitle = {12th International Conference on
Automated Deduction ({CADE-12})},
venue = {Nancy, France},
editor = {A. Bundy},
publisher = {Springer},
series = {LNCS},
volume = {814},
pages = {678--692},
year = {1994}
}