Harald Ganzinger Viorica Sofronie-Stokkermans Uwe Waldmann Modular proof systems for partial functions with Evans equality. 1453-1492 2006 204 Inf. Comput. 10 http://dx.doi.org/10.1016/j.ic.2005.10.002 db/journals/iandc/iandc204.html#GanzingerSW06