Methods to solve these equations.

A web text by Fred Barnes on 60-, 90-, and 120-degree integer-sided triangles.

A web tool for solving Diophantine equations of the form ax + by = c.

Articles, computations and software in Magma and GP by Martin Bright.

Some of conjectures and open problems, compiled at AIM.

On-line Pell Equation solver by Michael Zuker.

Record solutions.

John Robertson's treatise on how to solve Diophantine equations of the form x^2 - dy^2 = N.

Triangles in the Euclidean plane such that all three sides are rational. With tables of Heronian and Pythagorean triples.

Sets with the property that the product of any two distinct elements is one less than a square. Notes and bibliography by Andrej Dujella.