Spirits of North America is a book that focuses on paranormal entities found only in the North America region.
During the Radioactive Ghost case, a week old article about an excavation gone awry in Utah reminded Egon Spengler of ethereal entities from beliefs of aboriginal western peoples in western North America. He consulted "Spirits of North America" and told the Extreme Ghostbusters about the mountain spirit legend. 
- ↑ Egon Spengler (1997). Extreme Ghostbusters- Fallout (1997) (DVD ts. 06:49-07:06). Sony Pictures Home Entertainment. Egon says: "A mountain spirit. Some aboriginal peoples of western North America believed ethereal entities lived among the mesas and volcanic rock formations. Perhaps one of these spirits became trapped inside the mountain near the uranium deposit."