Stable subconstructs of FTS: Part II. - Robert Lowen; P. Wuyts (Fuzzy Sets Syst., 1995)

On level-topologies and maximality of fuzzy topological spaces. - P. Wuyts (Fuzzy Sets Syst., 1996)

Stable subconstructs of FTS - III (exotic cases). - Robert Lowen; Alain Verschoren; P. Wuyts (Fuzzy Sets Syst., 1998)

A Complete Classification of the Simultaneously Bireflective and Bicoreflective Subconstructs of Approach Spaces. - Robert Lowen; P. Wuyts (Appl. Categorical Struct., 2000)

Stable Subconstructs: A Correction and New Results. - Robert Lowen; P. Wuyts (Appl. Categorical Struct., 2011)