TY - RPRT TI - A variable frequency, variable selectivity filter for electroencephalography. AU - H C BECKER AU - W A MICKLE AU - R G HEATH PY - 1958 DO - 10.1016/0013-4694(58)90080-4 UR - https://pubmed.ncbi.nlm.nih.gov/13597824/ ID - 13597824 ER -