000 005260000a22001570004500
001 19997
090 _a19997
100 _a20190520 frey50
101 _aeng
200 0 1 _aA proposed biological measure of stream conditions, based on a survey of the Conestoga basin, Lancaster Country Pennsylvania
_fRuth Patrick
210 _a[S.l.]
_c1949
_d[s.n.]
215 _ap. 277-341
_cil.
_d28 cm
225 _aProceedings of the academy of natural sciences of Philadelphia
317 _aIPIMAR
676 _a0141 p
700 _aPatrick,
_bRuth