Funding for this research was provided by:
national university research institute
Text and Data Mining valid from 2019-06-11
Received: 6 February 2018
Accepted: 30 April 2019
First Online: 11 June 2019
Ethics approval and consent to participate
: This research was approved by the Ethical Committee of the International University of Africa, Khartoum Sudan and written consent was obtained.
: Not applicable.
: The authors declare that they have no competing interests.
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