1. A H Beiler, The Eternal Triangle, Ch. 14 in Recreations in the Theory of Numbers: The Queen of Mathematics Entertains. Dover, New York, 1966.
2. N J A Sloane, Sequences A001652/M3074, A001653/M3955, A001844/M3826, A005408/M2400, A046090, A046092, A095861, A101903, A101904 in The On-Line Encyclopedia of Integer Sequences.
3. T W Forget and T A Larkin, Pythagorean triads of the form X, X+1, Z described by recurrence sequences, Fib. Quart, Vol.6, No.3, pp.94–104, 1968.
4. Eric W Weisstein, Twin Pythagorean Triple, From MathWorld-A Wolfram Web Resource. http://mathworld.wolfram.com.TwinPythagoreanTriple.html
5. Difference Equations, from Wikipedia, the free encyclopedia.