Links and references from the episode:

* Wikipedia: Ring a Ring o’ Roses (https://en.wikipedia.org/wiki/Ring_a_Ring_o'_Roses)

* William Wells Newell: Games and Songs of American Children (https://books.google.com/books?id=6tvfAAAAMAAJ)

* Metafolklore: Ring Around the Rosie (https://blogs.loc.gov/folklife/2014/07/ring-around-the-rosie-metafolklore-rhyme-and-reason/)

* Wikipedia: San Francisco plague of 1900–1904 (https://en.wikipedia.org/wiki/San_Francisco_plague_of_1900%E2%80%931904)

* Youtube: Footloose "Dancing Warehouse" Scene (https://www.youtube.com/watch?v=j8XGmZ8HDIU)