00317nam a2200121 a 450000500170000008200210001710000180003811000180005624500230007426000320009730000240012949000420015320251203091603.0  a543.089,bD, wil  aWillett, John  aKealey, David  aGas chromatography  aSingaporebJohn Wileyc1987  axviii, 254p, 22 cm.  aAnalytical chemistry by open learning