See D. Willers, Hadrians panhellenisches Programm: Archäologische Beiträge zur Neugestaltung Athens durch Hadrian (Basel, Switzerland: Vereinigung der Freunde Antiker Kunst, 1990); Mary T. Boatwright, Hadrian and the City of Rome(Princeton: Princeton Univ. Press, 1987). See also, on the Pantheon, William L. MacDonald, The Architecture of the Roman Empire I: An Introductory Study, Yale Publications in the History of Art, no. 17 (New Haven and London: Yale Univ. Press, 1982).