1. 1. United States Environmental Protection agency. What is a HEPA filter? Updated April 26, 2022. Accessed December 1, 2021. https://www.epa.gov/indoor-air-quality-iaq/what-hepa-filter-1
2. 2. Cariolet R, Callarec J, Julou P, Pirouelle H, Le Gall L, Madec F, Caugant A. Validation et gestion d'unités protégées en élevage porcin [Validation and management of protected units in pig farming]. Journées Recherche Porcine France. 2000;32:25-32.
3. 3. Desrosiers R. Epidemiology, diagnosis and control of swine diseases. In: Proceedings of the 35th AASV Annual Meeting. American Association of Swine Veterinarians; 2004:1-30.
4. 4. Desrosiers R. Aerosol transmission of swine pathogens: Overview of the subject and evaluation of suspected field cases. In: Proceedings of the 36th AASV Annual Meeting. American Association of Swine Veterinarians; 2005:405-416.
5. 5. National American Filtration Association. Understanding MERV User Guide. Published October 2018. Accessed December 8, 2021. https://www.nafahq.org/understanding-merv-nafa-users-guide-to-ansi-ashrae-52-2