* {{CitationKaynak|last=King|first= Henry |title=Geared to the Stars: the Evolution of Planetariums, Orreries, and Astronomical Clocks|publisher= University of Toronto Press|date= 1978}}
* {{CitationKaynak|first=Edgar|last= Laird| title=Astrolabes and the Construction of Time in the Late Middle Ages.|journal=Constructions of Time in the Late Middle Ages|editor=Carol Poster and Richard Utz|location= Evanston, IL|publisher= Northwestern University Press|date= 1997| pages=51–69}}
* {{CitationKaynak|title=Critical edition of Pélerin de Prusse on the Astrolabe'' (translation of ''Practique de Astralabe''|editor1-first=Edgar| editor1-last=Laird| editor2-first=Robert|editor2-last= Fischer|location= Binghamton, New York|year= 1995|journal= ''Medieval & Renaissance Texts & Studies''| isbn= 0-86698-132-2}}
* {{CitationKaynak | last=Lewis | first=M. J. T. | date=2001 | title=Surveying Instruments of Greece and Rome| publisher=Cambridge University Press}}.
* {{CitationKaynak|first=John David|last= North|date=2005|title=God's Clockmaker: Richard of Wallingford and the Invention of Time|publisher= Continuum International Publishing Group|isbn=978-1-85285-451-5}}
