Pell Equation

http://mathworld.wolfram.com/PellEquation.html
http://sisbib.unmsm.edu.pe/bibvirtualdata/monografias/basic/alanya_ps/cap8.pdf http://www.math.fau.edu/Richman/pell-m.htm
http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/cfCALC.html
http://www.math.mtu.edu/mathlab/COURSES/holt/dnt/pell4.html
http://frontend.bioinfo.rpi.edu/zukerm/cgi-bin/dq.html

León-Sotelo