Circular 230 § 10.22
Diligence as to accuracy.
CFR 2001 annual edition (revised as of 2001-07-01) · in effect Jul 1, 1997 to Jul 1, 2003 · last amended by 57 FR 41095, Sept. 9, 1992
Each attorney, certified public accountant, enrolled agent, or enrolled actuary shall exercise due diligence:
(a) In preparing or assisting in the preparation of, approving, and filing returns, documents, affidavits, and other papers relating to Internal Revenue Service matters;
(b) In determining the correctness of oral or written representations made by him to the Department of the Treasury; and
(c) In determining the correctness of oral or written representations made by him to clients with reference to any matter administered by the Internal Revenue Service.