https://scholar.google.com/scholar_lookup?title=The+Presence+of+Acquired+Enamel+Pellicle+Changes+Acid-Induced+Erosion+from+Dissolution+to+a+Softening+Process&author=Mutahar,+M.&author=Carpenter,+G.&author=Bartlett,+D.&author=German,+M.&author=Moazzez,+R.&publication_year=2017&journal=Sci.+Rep.&volume=7&pages=10920&doi=10.1038/s41598-017-11498-1&pmid=28883656