Puerto Rico. Department of Public Works. Division of Investigations of Roads and Bridges

• Arroyo traffic study
• Puerto Rico road inventory report, 1955
• Statewide traffic survey, urban traffic volume study
• Urban street inventory, Arecibo, Puerto Rico, September 1955
• Urban street inventory, Ciales, Puerto Rico
• Urban street inventory, Isabela, Puerto Rico
• Urban street inventory, Lares, Puerto Rico, August 1955
• Urban street inventory, Quebradillas, Puerto Rico, August 1955
• Urban traffic volume study