The algebra of finitely additive measures on a partially ordered semigroup J. Pym; H. Vasudeva — 1977 Studia Mathematica
Flows on Invariant Subsets and Compactifications of a Locally Compact Group A. Lau; P. Milnes; J. Pym — 1998 Colloquium Mathematicae
On the two natural products in a Stone-Cech compactification . J. Pym; D. Strauss; A. El-Mabhouh — 1994 Semigroup forum