Healthline. https://www.healthline.com/health/tongue-color#diagnosis
Diakses pada 12 April 2020.
Cleveland Clinic. https://health.clevelandclinic.org/what-your-tongue-can-tell-you-about-your-health/
Diakses pada 12 April 2020.
Mens Health. https://www.menshealth.com/health/a23744710/tongue-color-causes/
Diakses pada 12 April 2020.