https://www.drbicuspid.com/dental-hygiene/hygiene-tools/article/15748657/what-you-need-to-know-about-xerostomia
https://www1.deltadentalins.com/wellness/conditions-and-treatments/articles/what-to-know-about-dry-mouth.html
https://www.oralhealthgroup.com/features/lips-the-forgotten-oral-tissue/
https://www.verywellhealth.com/why-is-my-mouth-so-dry-1059299