On the positivity of the unit element in a normed lattice ordered algebra S. Bernau; C. Huijsmans — 1990 Studia Mathematica
Unital Embedding and Complexification of F-Algebras. F. Beukers; C. Huijsmans; B.de Pagter — 1983 Mathematische Zeitschrift
Disjointness preserving and diffuse operators C. B. Huijsmans; B. de Pagter — 1991 Compositio Mathematica