Cleveland Clinic. https://health.clevelandclinic.org/mucus-and-phlegm-what-to-do-if-you-have-too-much/ Diakses pada 19 Januari 2021Healthgrades. https://www.healthgrades.com/right-care/ear-nose-and-throat/phlegm-symptoms Diakses pada 19 Januari 2021Healthline. https://www.healthline.com/health/overproduction-of-mucus-in-throat#treatment Diakses pada 19 Januari 2021Medical News Today. https://www.medicalnewstoday.com/articles/324980#medication Diakses pada 19 Januari 2021Medical News Today. https://www.medicalnewstoday.com/articles/coughing-up-phlegm-but-not-sick#phlegm-color Diakses pada 19 Januari 2021