https://www.mathworks.com/help/curvefit/least-squares-approximation-by-natural-cubic-splines.html
Least-Squares Approximation by Natural Cubic Splines - MATLAB & Simulink
The construction of a least-squares approximant usually requires that one have in hand a basis for the space from which the data are to be approximated.
least squares approximationcubic splinesnaturalmatlabsimulink
https://www.cambridge.org/core/journals/anziam-journal/article/best-least-squares-approximation-problem-for-a-3parametric-exponential-regression-model/7718BDC2113058BBEA73D0F97DEF76A6
The best least squares approximation problem for a 3-parametric exponential regression model | The...
The best least squares approximation problem for a 3-parametric exponential regression model - Volume 42 Issue 2
least squares approximation