Do you know what a "field guide" is? They're not generally full course textbooks on zoology.
If you want a more full treatment, I hear there's this "Believing Bullshit" book by, I don't know, some guy or other, I heard about it somewhere. (Haven't read it, so I can't guarantee it has any given thing, but I bet it's a good deal longer than that article.)
I think one is generally allowed to allude to belief in extraterrestrial visitation and psychic powers being a bit on the poorly-grounded side without popping open a footnote and pouring 150,000 words on the topic into it, especially in what is basically a sales pitch for a longer work.