000 00282nam a22001217a 4500
041 _aENG
100 _aThomas Kallard
245 _aElectret Devices For Air Pollution Control
260 _aNew Delhi
_bOptonic Press
_c1970
300 _a126
650 _aEOES (12)
856 _uEOES
999 _c2697
_d2697