See [here](https://doi.org/10.1016/j.amc.2006.06.074) for an example for a standard SIR. Requires a function to generate Adomian polynomials; example Maple code is [here](http://dx.doi.org/10.12988/imf.2006.06168), Mathematica code [here](https://www.sciencedirect.com/science/article/abs/pii/S0096300310007915) - there are many algorithms for this.
