There are no links to the official documents for the years 1989 through 1995. The information below can only be used as help for further research, as there is not enough information here to rely on for official guidance. For that you need to obtain a copy of the complete document.

Rev. Rul. 91-53
Federal rates; adjusted federal rates; adjusted federal long-term rate, and the long-term exempt rate. For purposes of sections 1274, 1288, 382, and other sections of the Code, tables set forth the rates for October 1991.

T.D. 8359
Final regulations under section 401 of the Code relate to permitted disparity with respect to benefits and contributions.

T.D. 8360
Final regulations under sections 401 and 411 of the Code relate to nondiscrimination requirements for qualified plans.

Announcement 91-146
A list is provided of organizations that no longer qualify as organizations contributions to which are deductible under section 170 of the Code.

ADMINISTRATIVE

Rev. Proc. 91-58
Backup withholding. Guidance is provided on how to stop backup withholding imposed by section 3406 of the Code after the Service has notified a payor of reportable payments twice within 3 calendar years that the taxpayer identification number provided by the payee to the payor is incorrect.