Monomorphisms and epimorphisms of inverse systems Luciano Stramaccia (1983) Commentationes Mathematicae Universitatis Carolinae
Monomorphisms in the categories of connected algebraic systems with strong homomorphisms Vítězslav Veselý, Ivan Kopeček (1976) Archivum Mathematicum
Monomorphisms in the category of small connected categories with surjective functors Josef Niederle (1977) Archivum Mathematicum