Cryptonym: ZRRIFLE
Flawed Patriot, by Bayard Stockton, Chapter 8
Chapter 8 of this book is devoted to Project ZR/RIFLE. From page 152: "The ZRRIFLE project name first appears, as far as is known, in May 1961, six months before Harvey was given the Castro assignment..."
The Road to Dallas, by David Kaiser, p. 77
from the book: Within the CIA, the new assassination program, code-named ZRRIFLE, was officially listed as an FID operation...
The Church Committee's Interim Report on CIA assassination plots delves into ZR/RIFLE at some length, and is an invaluable resource for understanding the "executive action" program.
104-10103-10318: HANDWRITTEN PAPER CONCERNING PROJECT ZRRIFLE
William Harvey's handwritten notes on project ZR/RIFLE is among the few documents about the project which were committed to paper. Ironically, it contains the admonitions "No projects on paper except for cover" and "never mention word assassination." It also contemplates the need for false documentation within CIA files to protect the operation from exposure: "Cover: planning should include provision for blaming Czechs or Sovs in case of blow" and "Should have phony 201 in RI to backstop this, documentation therein forged and backdated. Should look like a CE [CounterEspionage] file." Investigators of CIA records beware.
Paper on the ZRRIFLE files: PAPER ON THE ZRRIFLE FILES
This one-page excerpt has some interesting historical information about the project.
104-10425-10009: MEMO FOR: AUTHORIZATION OF ZRRIFLE AGENT ACTIVITIES
This memo to Harvey from Richard Helms provided specific authorization to hire QJWIN and others for project ZRRIFLE. It requests that "this activity be handled on an EYES ONLY basis."