Text and Data Mining valid from 2019-10-01
Received: 14 January 2019
Accepted: 24 September 2019
First Online: 1 October 2019
Ethics approval and consent to participate
: This study was reviewed and approved by Alzaiem Alazhari University—Sudan Research and Ethics Committee. Oral and written informed consents were obtained from participants’ or parents or guardians in case of children.
: Not applicable.
: The authors declare that they have no competing interests.