1. U.S. Food and Drug Administration . Guidance for the industry: modified risk tobacco product applications, 2012. Available: https://www.fda.gov/media/83300/download
2. U.S. Food and Drug Administration . FDA grants first-ever modified risk orders to eight smokeless tobacco products, 2019. Available: https://www.fda.gov/news-events/press-announcements/fda-grants-first-ever-modified-risk-orders-eight-smokeless-tobacco-products
3. U.S. Food and Drug Administration . FDA authorizes marketing of IQOS tobacco heating system with ‘reduced exposure’ information, 2020. Available: https://www.fda.gov/news-events/press-announcements/fda-authorizes-marketing-iqos-tobacco-heating-system-reduced-exposure-information
4. U.S. Food and Drug Administration . Modified risk tobacco products, 2020. Available: https://www.fda.gov/tobacco-products/advertising-and-promotion/modified-risk-tobacco-products
5. Heat-not-burn tobacco cigarettes: smoke by any other name;Auer;JAMA Intern Med,2017