BTK, The Transcript of his Guilty Plea.
This scholarly article discusses the atrocities and victims of Dennis Lynn Rader, specifically focusing in on his dormancy period before he was captured by police.
Published in August 2023 by the Journal of Student Research, written by Tatum Hayes and John Carl.
Here is the .PDF file I found from the fbi.vault.gov website. You can find them in there, but I wanted to include them here as well in a continued effort to be a one shop stop.