Hi Nick,
you did not specify the topic in more detail, so you may check the
following for the subjects you are interested:

J. Hoefs (1997, there is a newer edition) - Stable isotope
geochemistry, Springer, Berlin

Fritz, P. and Fontes, J.C. - Handbook of environmental isotope
geochemistry, Vol. 1. Elsevier, Amsterdam, 545 pp.
vol. 2 (1986); vol 3 (1989)

for special questions you can have look at:
J.W. Valley & D.R. Cole (2001) (eds.) Stable isotope geochemistry,
Reviews in Mineralogy and Geochemistry, 43

online resource:
<http://www.iaea.or.at/programmes/ripc/ih/volumes/volumes.htm>
<http://www.iaea.or.at/programmes/ripc/ih/publications/publications.htm>


greetings,
Robert
--
Dr. Robert van Geldern
Leibniz Institute for Applied Geosciences (GGA)
S3: Geochronology and Isotopehydrology
Stilleweg 2, 30655 Hannover, Germany
phone: +49-(0)511-643-2313, fax: +49-(0)511-643-3665
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