On filtered weighted colimits of presheaves F. Borceux, J. Rosický (2008) Cahiers de Topologie et Géométrie Différentielle Catégoriques
On some properties of pure morphisms of commutative rings. Mesablishvili, Bachuki (2002) Theory and Applications of Categories [electronic only]
On the External Characterization of Topological Functors. Harvey Wolff (1977) Manuscripta mathematica