Standard Approach to Estimating Volatility (Equation 15.1 Define on as the volatility per day between day n-1 and day n, as estimated at end of day n-1 · Define, as the value of market variable at end of day i Define ui= In(S /Si-1)

义务教育教科书：外研社版《初中英语》新版八年级上册英语电子课本（PDF电子书，无水印，New Standard English）

外研社版：《初中英语》义务教育教科书（新版七年级上册电子课本，无水印，New Standard English）