TY - RPRT TI - The difference between the potentiometric surfaces of the lower Patapsco aquifer, September 1990 and September 1999 in southern Maryland AU - Stephen E. Curtin AU - David C. Andreasen AU - Judith C. Wheeler PY - 2001 DO - 10.3133/ofr01211 UR - https://pubs.usgs.gov/publication/ofr01211 ID - ofr01211 ER -