The wikipedia page for automatic differentiation and its references would be a good start. https://en.wikipedia.org/wiki/Automatic_differentiation https://en.wi

The wikipedia page for automatic differentiation and its references would be a good start. https://en.wikipedia.org/wiki/Automatic_differentiation https://en.wikipedia.org/wiki/Automatic_differentiation In particular, the section "Beyond forward and reverse accumulation" tells you how hard it is to deal with the graph in optimal ways, hence the popularity of simpler forwards and backwards traversals of the graph.