On the Impossibility of Representing Certain Functions by Convolutions. Leonard Y.H. Yap — 1970 Mathematica Scandinavica
Factorization of Lipschitz Functioins and Absolute Convergence of Vilenkin-Fourier Series. Leonard Y.H. Yap; T.S. Quek — 1981 Monatshefte für Mathematik
Fourier Transforms of Lipschitz Functions and Fourier Multipliers on Compact Groups. Tong-Seng Quek; Leonard Y.H. Yap — 1983 Mathematische Zeitschrift
Sharpness of Young's inequality for convolution. Leonard Y.H. Yap; T.S. Quek — 1983 Mathematica Scandinavica