1. Boboshko MY, Lopotko Al. Eustachian tube. 2003. Russian.
2. Borysenko OM., Grynko 1.1. Results of eustachian tube function study in patients with chronic otitis media. Zhurnal vushnyh, nosovyh і gorlovyh hvorob. 2014; 3-s: 212. Ukrainian.
3. Kruk MB. Definition of patency of the eustachian tube with otitis media in terms. Bulleten of otolaryngology. 1973; 5: 48-53. Russian.
4. Kruk MM. Defining the functional status of eustachian tube in purulent otitis media. Zhurnal vushnyh, nosovyh і gorlovyh hvorob. 2011; 3: 134-135. Ukrainian.
5. Kruk MB, Kruk MM. About ventilation function of eustachian tube. Zhurnal vushnyh, nosovyh і gorlovyh hvorob. 2011; 3: 135. Ukrainian.