Esophageal achalasia and secondary megaesophagus in a dog Pedro A.Boria,Cynthia R.L.Webster,John Berg
file:///E:/C%20Drive/Megaesophagus%20for%20Dummies/Strictures/Esophageal%20Achalasia.pdf
Cricopharyngeal achalasia
https://wagwalking.com/condition/cricopharyngeal-achalasia
Achalasia in dogs
https://dogcare.dailypuppy.com/achalasia-dogs-7626.html