https://www.humantruth.info/tags/spirits.html
Human Truth Foundation pages (5):
Fake and Imaginary Ghosts: Some Stories are Simply Made Up
Ghosts, Physical Properties and Ghostly Clothes: A Skeptical Investigation
Spirit Dualism: It Makes No Sense to Divide Spirits Into "Good" and "Bad"
Souls do not Exist: Evidence from Science & Philosophy Against Mind-Body Dualism: 4.1. Ghosts
Not from the Human Truth Foundation, but still relevant (1):