World Health Organization. (2011). Psychological first aid: Guide for field workers. World Health Organization.
Dyfyniad Arddull ChicagoWorld Health Organization. Psychological First Aid: Guide for Field Workers. Geneva, Switzerland: World Health Organization, 2011.
Dyfyniad MLAWorld Health Organization. Psychological First Aid: Guide for Field Workers. World Health Organization, 2011.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.