Function Approximations Package References
 Hairer, E. and G. Wanner. Solving Ordinary Differential Equations II: Stiff and Differential‐Algebraic Problems. Springer, 1991.
 Iserles, A. and S. P. Nørsett. Order Stars. Chapman and Hall, 1991.
 Lambert, J. D. Numerical Methods for Ordinary Differential Systems: The Initial Value Problem. John Wiley and Sons, 1991.
 Sofroniou, M. "Order Stars and Linear Stability Theory." Journal of Symbolic Computation 21, no. 1 (1996): 101–131.