There is not really direct sources, everything you may want to learn from Orientalism could be found in Hegel's writing, Mark Twain even wrote about it, of course Himmler studied Sanskrit and the entire Ahnenerbe was focused on tracing German heritage back to India, which was all backed by Hegel when he wrote that the foundations of Europeans culture- German, Greek, Latin, was found only in Sanskrit. Mark Twain said something similar saying something along the lines of "All of Humanity's history is found treasured up in India only." Of course all of the reading from them could be considered mere lip service, but the discoveries by the Ahnenerbe checked everything out. Science's own contradictions is in of itself evidence supporting my claim. There is observable evidence too, such as the Indian phenotype which correlates with the indo-sythians, or modern day persians. and it is already well known that Persians moved westward and settled.