Greetings, Nanik, and welcome. You wrote:

<<This question has arisen from an individual who is a
68 yrs and three months old retired Professor. He has a 403b supplementary retirement account with TIAA-Cref, a 401K plan with his small private company which he founded several years ago and a small amount in an IRA from the days when his company did not have a 401K. He has heard on the radio confusing talks about minimum and lump sum withdrawls at age 70.5 and has not found
specific information or references on how to figure out how he should compute the minumum withdrawls, compare
the advantages and disadvantages of the alternatives
especially since he expects to continue working part time in his company for perhaps another 5 or 7 years depending on his health and may not need to draw upon much income from his retirement accounts until he is
completely retired.

Unfortunately TIAA says they can only advise on the
TIAA SRA alternatives and what is needed is advice
concerning the total of all retirement funds in the
context of wanting to leave any balances after his
needs to his heirs with a minimum of loss to estate taxes.

Any really pertinent references and responses will be
most appreciated. >>

Basically, your friend must begin minimum required distributions (MRD) from all his tax deferred plans no later than April 1 of the year following that in which he reaches age 70 1/2. If he is still working in his company at that time, he may postpone MRD from that 401k plan, but he will have to start withdrawals from the 403b and his IRAs). He will find the procedures for doing so explained in both IRS Publication 575 (Penison and Annuity Income) and IRS Publication 590 (Individual Retirement Arrangements). The discussions in both start on page 35 and on page 21, respectively. In general, using a non-spousal beneficiary and computing withdrawals based on a joint life expectancy will benefit both him and his children from an income tax standpoint; however, he should consult with his tax advisor prior to making such an election. Once the method of withdrawal is chosen, it cannot be changed.

Regards..Pixy