Smith C I, Chamberlain A T, Riley M S, Cooper A, Stringer C B, Collins M J
Fossil Fuels and Environmental Geochemistry (Postgraduate Institute), NRG, Drummond Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, UK.
Nature. 2001 Apr 12;410(6830):771-2. doi: 10.1038/35071177.