Arctangent function, and efficient approximations, Arctangent function, in signal processing real-time applications, Four-quadrant arctangent approximations, the range extended, Lagrange interpolation-based and minimax criterion-based, Third-order approximation, and least error among approximations
doi.org/10.1002/9781118316948.ch27
Department of Systems and Computer Engineering

Rajan, S, Wang, S. (Sichun), Inkol, R. (Robert), & Joyal, A. (Alain). (2012). Efficient Approximations for the Arctangent Function. In Streamlining Digital Signal Processing: A Tricks of the Trade Guidebook: Second Edition (pp. 265–276). doi:10.1002/9781118316948.ch27