00305nam a2200085Ia 4500008004100000100001900041245011600060260003100176300001200207220214s9999    xx            000 0 und d  aWilkiebJohn B. 0aCorrections for background in spectrophotometry using difference-in-absorbance values. Application to Vitamin A  bAnalytical Chemistryc1964  a896-900