Dietary Supplement Health and Education Act, 42 USC §485C (1994).
https://ods.od.nih.gov/About/DSHEA_Wording.aspx

National Institutes of Health; Friends of the National Library of Medicine. The importance of sleep. NIH Medline Plus®. 2012;7(2):17.
https://magazine.medlineplus.gov/pdf/MLP_Summer2012web.pdf.

What is Melatonin?
https://www.sleep.org/how-sleep-works/melatonin/.

Melatonin and Sleep
https://www.sleepfoundation.org/melatonin

Here's What Happens When You Don't Get Enough Sleep (and How Much You Really Need a Night)
https://health.clevelandclinic.org/happens-body-dont-get-enough-sleep/

Stay Awake On The Road: Combat Drowsy Driving
https://www.sleepfoundation.org/drowsy-driving/how-to-stay-awake-tips

Caffeine & Sleep Problems
https://www.sleepfoundation.org/nutrition/caffeine-and-sleep

How To Sleep Better
https://www.sleepfoundation.org/sleep-hygiene/healthy-sleep-tips

Twelve Simple Tips To Improve Your Sleep
http://healthysleep.med.harvard.edu/healthy/getting/overcoming/tips

Put the Phone Away! 3 Reasons Why Looking At It Before Bed Is a Bad Habit
https://health.clevelandclinic.org/put-the-phone-away-3-reasons-why-looking-at-it-before-bed-is-a-bad-habit/

8 Secrets To a Good Night's Sleep | Harvard Publishing
https://www.health.harvard.edu/sleep/8-secrets-to-a-good-nights-sleep

Workouts That You Can Try For a Better Night's Sleep Tonight
https://www.sleep.org/exercises-improve-sleep/

How much sleep do you need?
https://www.sleep.org/how-sleep-works/how-many-hours-of-sleep-do-we-need/

9 Sleep Habits From Around the World | Abigail Abrams
https://time.com/4713813/sleep-habits-napping-siesta/

Which Countries Get The Most (and Least) Sleep?
https://www.sleepadvisor.org/countries-most-sleep

Exercising For Better Sleep
https://www.hopkinsmedicine.org/health/wellness-and-prevention/exercising-for-better-sleep

Does Exercising At Night Affect Sleep? | Harvard Publishing
https://www.health.harvard.edu/staying-healthy/does-exercising-at-night-affect-sleep

The Top 3 Workouts (cardio, Strength, and Yoga) For Better Sleep
https://www.sleepfoundation.org/physical-activity/best-exercises-sleep

Workouts That You Can Try For a Better Night's Sleep Tonight
https://www.sleep.org/how-sleep-works/exercise-affects-sleep/