Opial Inequalities with Applications in Differential and Difference Equations R. P. Agarwal, P. Y. Pang E-Book (pdf)

Error Inequalities in Polynomial Interpolation and Their Applications R. P. Agarwal, Patricia J. Y. Wong E-Book (pdf)

Oscillation Theory for Difference and Functional Differential Equations R. P. Agarwal, Said R. Grace, Donal O'Regan E-Book (pdf)