§ 3003. Content of tax due, deficiency, and other notices. Any first
letter of proposed deficiency or determination (commonly called a thirty
day letter) issued by the commissioner, and any notice and demand,
notice of deficiency or notice of determination which is issued by the
commissioner, which is manually initiated and which is the first such
letter or notice issued to the taxpayer with respect to the subject
matter of such notice, shall describe the basis for (such as the
statutory or regulatory law, or judicial or tax appeals tribunal
decision), and identify the amounts (if any) of the tax due. An
inadequate description under this section shall not invalidate such
letter or notice.