Chronic Disease Prevention and Health Promotion, CDC, 2010. Preventing Chronic Disease: Eliminating the Preventable Causes of Premature Death and Disability in the US. Retrieved from https://www.cdc.gov/chronicdisease/pdf/preventing-chronic-disease-508.pdf.
Duke University. "Why are habits so hard to break? Getting hooked changes the brain, scientists say." ScienceDaily. 21 Jan 2016. Retrieved from www.sciencedaily.com/releases/2016/01/160121130015.htm.