DNA damage in UV-irradiated human skin in vivo: automated direct analysis (thymine dimers) compared with indirect measurement measurement by image (unscheduled DNA synthesis) and protection by 5-methoxypsoralen - Potten, C S; Chadwick, C A; Cohen, A J; Nikaidos, O; Matsunaga, T; Schipper, N W; Young, A R (Int J Radiat Biol, 1993)