Arrays of such sensors are constructed with {TAIL ~ at least two sensors} having different chemically sensitive resistors providing {HEAD ~ dissimilar such differences} in resistance 
Arrays of such sensors are constructed with { TAIL ~ at least two sensors } having different chemically sensitive resistors providing { HEAD ~ dissimilar such differences } in resistance
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH