While Patty Duke's Wikipedia entry calls him "John Brock Duke,"
[1] there is no middle name in the 1920, 1930 or 1940 census records. Ethnicelebs and FindAGrave refer to him as John "Patrick" Duke.[2][3]
↑Find A Grave, database and images (accessed 07 February 2020), memorial page for John Patrick Duke (9 May 1913–8 Feb 1964), Find A Grave: Memorial #184119864, citing Long Island National Cemetery, East Farmingdale, Suffolk County, New York, USA; Maintained by J Smith (contributor 47377896).
"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MJBC-2SL : accessed 31 March 2016), John Duke in household of James Duke, Manhattan Assembly District 12, New York, New York, United States; citing sheet 8A, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 1,821,206.