For purposes of dealing with the Internal Revenue Service, this ranking correctly reflects the relative authority of the indicated tax law sources: Regulations > Revenue Ruling > Revenue Procedures >>> Action on Decision, Announcements, General Council Memoranda, Letter Rulings, Notices, Prohibited Transaction Exemptions, Technical Advice Memoranda (">>>" preceding a particular tax law source indicates that that source of law does not carry substantial authority). true of false, I need reasons and links to tell me why.