Gringo Builders: The First Big Water Projects. by J.L. Allhands, 1931.
"Application for CCID Texas Historical Marker Application" by Buddy Dosset, 1996.
Rio Grande Heritage, A Pictorial History. by Brian Robertson, 1985.
"A Study of Frank Seldon Robertson" by Minnie Gilbert, Roots by the River, 1978
All attached/scanned photos, courtesy of San Benito Historical Society.