
Is there a technical error in the Garmam-Klass volatility estimator paper?
Paper: https://www-2.rotman.utoronto.ca/~kan/3032/pdf/FinancialAssetReturns/Garman_Klass_JB_1980.pdf
Could anyone confirm whether equation 11 is correct?
I was under the impression that a Jacobian scaling factor of \lambda^3 is required for the equality to hold mathematically?
EDIT: Changed question to focus on the correctness of eqn 11 rather than eqn 12.