http://en.wikipedia.org/wiki/Curve_fitting
http://www.ce.ufl.edu/~kgurl/Classes/Lect3421/NM5_curve_s02.pdf
http://www.csupomona.edu/~seskandari/documents/Curve_Fitting_William_Lee.pdf
http://zeus.df.ufcg.edu.br/labfit/
http://www.swarthmore.edu/NatSci/echeeve1/Ref/MatlabCurveFit/MatlabCftool.html
http://www.uccs.edu/~eboggess/Math2650Lab7.pdf
http://en.wikipedia.org/wiki/Least_squares
http://dwb4.unl.edu/chem/chem869y/chem869ymats/least_squares.html
http://www.uwyo.edu/ceas/classes/meref/curve_fitting.pdf
http://libraries.maine.edu/Spatial/gisweb/spatdb/acsm/ac94053.html
http://maxwell.ucsc.edu/~drip/133/ch3.pdf
http://www.math.uiuc.edu/~franklan/Math416_LeastSquares.pdf
http://www.angelfire.com/ak4/neurope/ls.html
http://www.mafy.lut.fi/study/NLOpt/fitting.pdf
http://statpages.org/nonlin.html
http://www-ee.ccny.cuny.edu/www/web/yltian/Engr%20103%20Lesson%2014.PDF
http://www.efunda.com/math/leastsquares/leastsquares.cfm
http://www.prz.rzeszow.pl/~janand/
http://www.faculty.umassd.edu/michele.mandrioli/424book/fchm10.3.html
http://mathworld.wolfram.com/LeastSquaresFittingPolynomial.html
http://scholar.noctrl.edu/dahorner/links/weighted-least-squares-example
http://www.stat.cmu.edu/~cshalizi/350/lectures/18/lecture-18.pdf
http://www.utdallas.edu/~herve/Abdi-LeastSquares-pretty.pdf