good question! the internet frankly... I know it isn't much... yes you are probably right! you guys search for texts in dozens of books... and document your writing I simply search historical web pages and try to get to a conclusion... thank you for reminding me you are trying to recreate history too not only creating a "simulation of war"!
Edit: well I also read some online books but only scraps that interest me, to get to a more documented conclusion... but I don't keep them recorded...