found: Napoleon III in England, 1952:title page (Ivor Guest)
found: Adventures of a ballet historian, c1982:title page (Ivor Guest)
found: The Paris Opéra ballet, 2006:title page (Ivor Guest)
found: BL auth. file, 22 Jan. 2007(hdg.: Guest, Ivor, 1920-)
found: Wikipedia, May 23, 2016(Ivor Guest. Born 14 April 1920, Chislehurst, England. Occupation: historian, lawyer and administrator ; best known as a historian for his study of ballet)
found: El país WWW site, viewed April 9, 2018(in obituary dated April 8, 2018: Ivor Guest; the most imporant ballet historian of our time, Ivor Forbes Guest, died in London at age 97 on March 30; born April 14, 1920, Chislehurst, Kent)