The use of visual analogue scales to assess motivation to eat in human subjects: a review of their reliability and validity with an evaluation of new hand-held computerized systems for temporal tracking of appetite ratings - Stubbs, R J; Hughes, D A; Johnstone, A M; Rowley, E; Reid, C; Elia, M; Stratton, R; Delargy, H; King, N; Blundell, J E (Br J Nutr, 2000)