Uniform limits of Darboux functions on the Euclidean plane H. W. Pu; H. H. Pu — 1989 Colloquium Mathematicae
On level sets of approximate derivative and approximate symmetric derivative H. H. Pu; H. W. Pu — 1987 Colloquium Mathematicae
An approximative generalization of Zahorski's theorem on derivative H. H. Pu; H. W. Pu — 1978 Colloquium Mathematicae
On the set where an approximate derivative is a derivative H. H. Pu; H. W. Pu — 1980 Colloquium Mathematicae