Reptile studies

I'm curious to know if there are any good studies out there on reptile substrates? I know there are sites where necropsies have been performed on bearded dragons and leopard geckos to show impaction of certain substrates. But are there any where reptiles have been studied as to which substrates they eat and why? I've only heard theories. There should be some studies like this. I know there are studies like this done on uvb. The main one is that one infamous European study. the only thing about that one is that it is terribly out of date. Its good to use as a reference for some general principles. However, its not that great when using it as a reference as to what types of bulbs are safe anymore because some of the bulbs that were listed in the study are ok now. Like I remember people on the internet giving me lip from time to time because I used Zilla lights for my bearded dragons. I got the ones that were redone after the study had come out (50 series). They're great bulbs but just get a bad rap sometimes because the site is outdated. But despite that, at least a study was done. Theres nothing like that for substrate use. Thats why I'm asking.