A magnificent gilt-brass Ptolemaic armillary sphere,
Henri Michel Scientific Instruments in Art and History (London, 1967), no. 48 for a picture of the 1575 Arsenius armillary sphere
Henry C. King, with J.R. Millburn Geared to the Stars: The Evolution of Planetariums, Orreries and Astronomical Clocks (Toronto and Bristol, 1978), especially chapter 2
Dictionary of Scientific Biography (New York, 1970-80), Brahe, Tycho; Ptolemy, Claudius
Christie's catalogue The Murad III Globes Christie's King Street, 30 October 1991, lot 139.
G.L'E. Turner and E. Dekker "An Astrolabe attributed to Gerard Mercator circa 1570", Annals of Science, 50 (1993), pp. 403-443
G.L'E. Turner "The Three Astrolabes of Gerard Mercator", Annals of Science, 51 (1994), pp. 329-353