1. Australian/New Zealand Standard. 2003. “Respiratory Protective Devices.”, Sydney, Australia: Standards Australia, AS/NZS 1716: 2003
2. Comite Europeen de Normalisation. 2002. “Respiratory Protective Devices. Methods of Test: Determination of Carbon dioxide Content of the Inhalation Air.”, Dublin, Ireland: National Standards Authority of Ireland, EN 13274-6:2002