Kamerling, Bruce (December 1987). "California's Leonardo: The Portraits of Signor Barbieri". California History. 66 (4): 262–277. doi:10.2307/25177285. JSTOR25177285.
Kamerling, Bruce (December 1987). "California's Leonardo: The Portraits of Signor Barbieri". California History. 66 (4): 262–277. doi:10.2307/25177285. JSTOR25177285.