Aida Pliuskeviciene Regimantas Pliuskevicius Michal Walicki Sigurd Meldal On Specialization of Derivations in Axiomatic Equality Theories. 291-303 1994 conf/lfcs/1994 LFCS db/conf/lfcs/lfcs1994.html#PliuskevicienePWM94