Acknowledgement
I would like to express my deepest gratefulness to my lecturer, Dr.
Nurul Ain Mohd Tahir for her patience, guidance and assistance
throughout the study. I would also like to thank Professor Shu Chuen Li
for always being willing to help and give excellent ideas for
improvement. Lastly, I would also like to show my appreciation to my
teammate, Geok Ying for helping me through the process of conducting a
systematic review.