...
The American Institute of Architects Archives
Membership file includes application, correspondence on various topics. Obituaries. His Fellowship nomination is not in the AIA Archives.
William L. Steele's membership file includes a transcript of the memorial tribute given by Steele at the AIA Convention.
History Nebraska (Nebraska State Historical Society)
Thomas Rogers Kimball Collection, RG3607. A finding aid exists but is not online https://history.nebraska.gov/collections/manuscript-collections/personal-and-family-papers/. A biography and links to selected digitized images are available http://www.e-nebraskahistory.org/index.php?title=Thomas_Rogers_Kimball_(1862-1934),_Architect