yeah, I don’t like how McGowan doesn't include sources for anything. But it's an interesting read nonetheless.
If you're looking for an academic account of this top-secret film studio, "Lookout America! The Secret Hollywood Studio at the Heart of the Cold War" is a far better choice. There aren't any digitized versions of this one though
https://press.uchicago.edu/ucp/books/book/distributed/L/bo44434986.html