As far as I can remember watchtower has been notorious for not citing their sources in their literature. The most they will do is to cite their in house, long living expert by the name of Scholar. After 40 + years all i've ever read is the mantra "one scholar says" Ad nauseum
But low and behold on their website page directed at "clinicians", they feature a number of medical articles from Pubmed (NCBI) all in proper citation AMA format.
So they know what to do when it comes to presenting and citing sources properly when the audience is made up of worldly professional folk. But they wont do the same for their own people. They are duplicitious and deceitful and just don't want the sheep to know where they are getting the information.
I recently read a quote online by a Maximilien Rosespierre that said: The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant.