"IBM Archives: Frequently Asked Questions"(PDF). Archived from the original(PDF) on May 14, 2005. Some accounts of the forming CTR state that only three corporations were included. This reference notes that only three of the four corporations are represented in the CTR name. That may be the reason for the differing accounts.
immigrantentrepreneurship.org
"Herman Hollerith". Immigrant Entrepreneurship. Retrieved June 25, 2024.
O'Connor, J. J.; Robertson, E. F."Herman Hollerith". The MacTutor History of Mathematics Archive. School of Mathematics and Statistics, University of St Andrews, Scotland. Retrieved August 12, 2024.
"IBM Archives: Frequently Asked Questions"(PDF). Archived from the original(PDF) on May 14, 2005. Some accounts of the forming CTR state that only three corporations were included. This reference notes that only three of the four corporations are represented in the CTR name. That may be the reason for the differing accounts.
