TY - RPRT TI - Fractionation and characterization of natural organic matter from certain rivers and soils by free-flow electrophoresis AU - J.A. Leenheer AU - Ronald L. Malcolm PY - 1973 DO - 10.3133/wsp1817e UR - https://pubs.usgs.gov/publication/wsp1817E ID - wsp1817E ER -