TY  - RPRT
TI  - Methods for collecting algal samples as part of the National Water-Quality Assessment Program
AU  - Stephen D. Porter
AU  - Thomas F. Cuffney
AU  - Martin E. Gurtz
AU  - Michael R. Meador
PY  - 1993
DO  - 10.3133/ofr93409
UR  - https://pubs.usgs.gov/publication/ofr93409
ID  - ofr93409
ER  -