Text and Data Mining valid from 2019-10-28
Received: 16 August 2019
Accepted: 17 October 2019
First Online: 28 October 2019
Ethics approval and consent to participate
: Ethical clearance was obtained from the institutional review board of the University of Gondar. The parents or guardians of the children were briefed for the aim of the study and finally written consent was taken.
: Not applicable.
: The authors declare that they have no competing interests.