Khoo, T. K., Yarnall, A. J., Duncan, G. W., Coleman, S., O’Brien, J. T., Brooks, D. J., . . . Burn, D. J. (2013). The spectrum of nonmotor symptoms in early Parkinson disease. Lippincott Williams & Wilkins.

Khoo, Tien K., Alison J. Yarnall, Gordon W. Duncan, Shirley Coleman, John T. O’Brien, David J. Brooks, Roger A. Barker, và David J. Burn. The Spectrum of Nonmotor Symptoms in Early Parkinson Disease. Lippincott Williams & Wilkins, 2013.

Khoo, Tien K., et al. The Spectrum of Nonmotor Symptoms in Early Parkinson Disease. Lippincott Williams & Wilkins, 2013.