Varieties of an enriched category Brian J. Day (1978) Cahiers de Topologie et Géométrie Différentielle Catégoriques
Varieties of associative rings closed under ideal sums Michael V. Volkov (1983) Commentationes Mathematicae Universitatis Carolinae
Varieties of Ockham algebras satisfying x ≤ f 4 ( x ) Sequeira, Margarida (1988) Portugaliae mathematica
Varieties of quasigroups determined by short strictly balanced identities Jaroslav Ježek, Tomáš Kepka (1979) Czechoslovak Mathematical Journal
Varieties with modular and distributive lattices of symmetric or reflexive relations Ivan Chajda (1992) Czechoslovak Mathematical Journal