Transfer pricing reference rules govern when the arm's length price may be determined by the Transfer Pricing Officer. Reference to the Transfer Pricing Officer is permitted where the assessee has entered into an international transaction or specified domestic transaction and the Assessing Officer considers the reference necessary or expedient, with previous approval of the Principal Commissioner or Commissioner. The Transfer Pricing Officer must call for evidence, consider all relevant material, and determine the arm's length price by written order, with the Assessing Officer then computing income in conformity with that determination. The provision also covers validity of the assessee's option for similar transactions in the two succeeding tax years, rectification of mistakes, limitation periods, delegated powers, and issuance of guidelines to remove difficulties.