Research proposal literature review

The following requirements should be met in your literature review:
Article links
http://www.nepjol.info/index.php/JoNMC/article/viewFile/7296/5912
http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0117999&type=printable
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4803976/
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0078412
The other article are attaced