Byers, 1977, DESTINATION MOON: A history of the Lunar Orbiter Program (PDF), NASA TM X-3487*DESTINATION MOON: A history of the Lunar Orbiter Program (PDF) 1977, NASA TM X-3487*DESTINATION MOON: A history of the Lunar Orbiter Program (HTML)The above links lead to a whole book on the Lunar Orbiter program.
* DESTINATION MOON: A history of the Lunar Orbiter Program (PDF) 1976