003340000a22001210004500060000800000082002100008100001800029245004200047260003400089260000900123300000800132650007200140  a100  a541.  372  8 GRA  aGrant, Julius  aMeasurement of hydrogen concentration  aLondon, Longmans, green & co.  c1930  a159  aHydrogen ion concentration/electrometric method/colorimetric method