Ali, M. A., Haque, A., Anwarulla, A., & Ahmad, Q. (2009). Non–motor Symptoms in Parkinson’s Disease: It’s Relationship with Age of Onset, Duration and Stage of Disease and the Dose and Duration of Levodopa Usage. TAJ: Journal of Teachers Association, 21(1), 12–17. https://doi.org/10.3329/taj.v21i1.3211