TY  - BOOK
AU  - Tomlin,K.
ED  - Global Environmental Monitoring System.
TI  - Low cost monitoring for freshwaters: field techniques 
PY  - 1989///
CY  - London
PB  - GEMS Monitoring and Assessement Research Centre, University of London
KW  - Freshwater ecology
N1  - Includes bibliographical references; Open access
ER  -