Lexicographic Orthogonality. - David J. Foulis; C. H. Randall (J. Comb. Theory A, 1971)

States and the Free Orthogonality Monoid. - C. H. Randall; David J. Foulis (Math. Syst. Theory, 1972)

The Universal Group of a Heyting Effect Algebra. - David J. Foulis (Stud Logica, 2006)

Projections in a Synaptic Algebra. - David J. Foulis; Sylvia Pulmannová (Order, 2010)

Lattice pseudoeffect algebras as double residuated structures. - David J. Foulis; Sylvia Pulmannová; Elena Vinceková (Soft Comput., 2011)

Logical Connectives on Lattice Effect Algebras. - David J. Foulis; Sylvia Pulmannová (Stud Logica, 2012)

Unitizing a Generalized Pseudo Effect Algebra. - David J. Foulis; Sylvia Pulmannová (Order, 2015)

Unitizations of Generalized Pseudo Effect Algebras and their Ideals. - David J. Foulis; Sylvia Pulmannová; Elena Vinceková (Order, 2016)

Spectral Order on a Synaptic Algebra. - David J. Foulis; Sylvia Pulmannová (Order, 2019)