TY - RPRT TI - The deethylatrazine/atrazine ratio as an indicator of the onset of the spring flush of herbicides into surface water of the Midwestern United States AU - E.M. Thurman AU - J. D. Fallon PY - 1996 DO - 10.1080/03067319608045555 UR - https://pubs.usgs.gov/publication/70185707 ID - 70185707 ER -