↑ Anthony Aveni, "May Day: A Collision of Forces," The Book of the Year: A Brief History of Our Seasonal Holidays (Oxford: Oxford University Press, 2004), 79-89.
↑ Bliss, William Dwight Porter (1909). The new encyclopedia of social reform. 1. Funk & Wagnalls. p. 77.
↑ Journeymen Stone Cutters' Association of North America (1922). The Stone cutters' journal. Journeymen Stone Cutters Association of North America. 37-39: 18. Missing or empty |title= (help)
