TY  - GEN
AU  - Thomas, William A
TI  - Indicators of environmental quality: proceedings of a symposium held during the AAAS meeting in Philadelphia, Pennsylvania, December 26-31, 1971
SN  - 0306363011
U1  - 620.8 THO 
CY  - Newyork, Plenum press
KW  - Enviornmental quality-congresses/plant indicator-ecological aspects
ER  -