Brown, R.G., Landau, S., Hindle, J.V., Playfer, J., Samuel, M., Wilson, K.C., Hurt, C.S., Anderson, R.J., Carnell, J., Dickinson, L., Gibson, G., van Schaick, R., Sellwood, K., Thomas, B.A., Burn, D.J., for the PROMS-PD Study Group,, "Depression and anxiety related subtypes in Parkinson's disease", JOURNAL OF NEUROLOGY NEUROSURGERY AND PSYCHIATRY, 2011