Sparavigna A., (2012) Roman Dodecahedron as dioptron: Analysis of freely available data, Arxiv, [1]
dodecaeder.nl
Wagemans G.M.C., The Roman Pentagon Dodecahedron, An Astronomic Measuring Instrument for Determining the optimal sowing date for winter grain[2]; this webpage also has a map of the distribution of the dodecahedra
