References
Good Roads Everywhere A History of Road Building in Arizona - Arizona Department of Transportation
Arizona Transportation History - Arizona Department of Transportation
Beale's Report to the Secretary of War
Beale's Wagon Road - Wikipedia
Report of the State Engineer 1909-1914
Second Biennial Report of the State Engineer 1914-1916
Third Biennial Report of the State Engineer 1916-1918
Fourth Biennial Report of the State Engineer 1918-1920
Fifth Biennial Report of the State Engineer 1920-1922
Sixth Biennial Report of the State Engineer 1922-1924
Seventh Biennial Report of the State Engineer 1924-1926
Cool Springs to Oatman - Road Trip USA
National Scenic Byways & All-American Roads Arizona - Federal Highway Administration
Map of Historic Route 66 Arizona Eastern Section - Federal Highway Administration
Map of Historic Route 66 Arizona Western Section - Federal Highway Administration
Black Bridge - Arizona State University
Arizona Route 66 Corridor Management Plan - Arizona Department of Transportation
Database of Historic Bridges in Arizona - Jim Ross