Walter Rehm: Jakob Burckhardt und Franz Kugler In: Basler Zeitschrift für Geschichte und Altertumskunde. Band 41, 1942, doi:10.5169/seals-115350#159, S. 155–252.
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Eadmund Head: A Hand-Book of the History of the Spanish and French Schools of Painting – Intended as a Sequel to “Kugler’s Hand-Books of the Italian, German and Dutch Schools of Painting”. London 1848 (books.google.de).