Refs.:
- Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 893.
- Cooper, M.P. and Stanley, C.J. (1991). "Famous mineral localities : Pyromorphite group minerals from the Caldbeck Fells Cumbria England." Mineralogical Record, 22(2), 105-122.
- Cooper, M.P. and Stanley, C. (1997). "Die Mineralien von Caldbeck Fells, Cumberland, England." Lapis 22(3), 13-34 (in German).
