World Health Organization. (2011). Psychological first aid: Guide for field workers. World Health Organization.
Chicago Style aipamenaWorld Health Organization. Psychological First Aid: Guide for Field Workers. Geneva, Switzerland: World Health Organization, 2011.
MLA aipamenaWorld Health Organization. Psychological First Aid: Guide for Field Workers. World Health Organization, 2011.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.