Reference to the CD-ROM should be as follows:
BGS (2007). Peru Regional Geochemical Exploration Survey CD-Rom. Version 2.0. BGS International Regional Geochemistry CD-Rom Series. No 4. Peru. British Geological Survey, Keyworth, Nottingham, UK.
The CD-ROM also contains the following:
Baldock, J W. 1971. Geochemical Exploration of Northern Peru (GENP), 1967-71. (Unpublished report of the project).