BS 5688-28:1986 Digital PDF

Methods of test for orthoboric acid (boric acid), diboron trioxide (boric oxide), disodium tetraborates, sodium perborates and crude sodium borates for industrial use-Determination of total and alkali-soluble calcium and magnesium contents of crude sodium borates (flame atomic absorption spectrometric method)
standard by BSI Group, 07/31/1986