Consistency of the BIC order estimator. Csiszár, Imre; Shields, Paul C. — 1999 Electronic Research Announcements of the American Mathematical Society [electronic only]
Invariant Elements for Positive Contractions on a Banach Lattice. Paul C. Shields — 1967 Mathematische Zeitschrift
A Mixing T for which T - T... Is Bernoulli. Paul C. Shields; Robert M. Burton — 1983 Monatshefte für Mathematik