Conscientious objector
76–78. Mennoniite Publishing House.
Magelssen, Morten. "When should conscientious objection be accepted?"  Journal of Medical Ethics 38.1 (2012): 18–21. online
Matthews, Mark (2006). Smoke Jumping on the Western Fire Line: Conscientious Objectors during World War II, University of Oklahoma Press. ISBN 978-0806137667
Moorehead, Caroline (1987). Troublesome People: Enemies of War, 1916–86, Hamish Hamilton Ltd, ISBN 0-241-12105-1
Quakers in Britain — Conscientious Objectors.
Smith, C. Henry (1981). Smith's Story of the Mennonites. Revised and expanded by Cornelius Krahn. Newton, Kansas: Faith and Life Press. pp. 299–300, 311. ISBN 0-87303-069-9.
Robb, Linsey. "The 'Conchie Corps': Conflict, Compromise and Conscientious Objection in the British Army, 1940–1945." Twentieth Century British History 29.3 (2018): 411–434. online
Tinnelly CM, Joseph T. "The Conscientious Objector Under the Selective Service Act of 1940." St. John's Law Review 15.2 (2013): 6+ online.

Primary sources: Bennett, Scott H. (2005). Army GI, Pacifist CO: The World War II Letters of Frank and Albert Dietrich (Fordham Univ. Press).
McNair, Donald (2008) A Pacifist at War: Military Memoirs of a Conscientious Objector in Palestine 1917–1918 Anastasia Press, Much Hadham ISBN 978-0-9536396-1-8
Mock, Melanie Springer (2003). Writing Peace: The Unheard Voices of Great War Mennonite Objectors, Cascadia Publishing House. ISBN 1-931038-09-0
U.S. Selective Service, "Conscientious Objection and Alternative Service: Who Qualifies Archived 2017-04-27 at the Wayback Machine"

Further viewing: Rick Tejada-Flores, Judith Ehrlich (2000), "The good war and those who refused to fight it"; Paradigm Productions in association with the Independent Television Service, aired on PBS.
Catherine Ryan, Gary Weimberg (2008), "Soldiers of Conscience"; Luna Productions. Aired on the PBS nonfiction series POV.
Molly Stuart, Amitai Ben-Abba (2019), "Objector"; Java Films. A documentary about Israeli conscientious objector Atalya Ben-Abba, premiered at IDFA. – "Objector". IMDb. 2019. Retrieved 2 October 2021.

External links: 
Schleif, Luke: Conscientious Objectors, in: 1914-1918-online. International Encyclopedia of the First World War.
Patterson, David S.: Pacifism, in: 1914-1918-online. International Encyclopedia of the First World War.
Alternative Service in the Second World War: Conscientious Objectors in Canada 1939–1945
The National Registry for Conscientious Objection
International Conscientious Objectors' Day (War Resisters' International)
of Human Rights factsheet on case law on conscientious objection
"Making a Choice: Conscientious Objection or Refusing to Register" (Resisters.info)
The European Bureau for Conscientious Objection
Refusing to Kill: conscientious objection and human rights in World War I. Peace Pledge Union, 2006.
Watch His Conscience: A Short History Of The Conscientious Objector. By Michael D. Peabody
Catholic Peace Fellowship
The Right to Refuse to Bear Arms – the most authoritative recent world survey on provisions for conscientious objection to military service, by War Resisters' International
A Conscientious Objector's Guide to the UN Human Rights System
You have no enemies. A Call for Conscientious Objection. By Dieter Duhm
"Hacksaw Ridge" A film about conscientious objector, Desmond T.Doss who received 'Medal of Honor' in WW2.
Objector – a 2019 documentary about Israeli conscientious objector Atalya Ben-Abba.
International Conscientious Objectors' Day