Can you suggest information sources about tax rules about annual retirement savings limits and deductions applicable to married couples filing jointly by income? Tx.

Go to a bookstore or library and see what you like that is written to your level of need.  I don't know that any of us will recommend a specific author.

Regarding 401k and retirement accounts, some IRS information is here.

https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-ira-contribution-limits

https://www.irs.gov/newsroom/401k-limit-increases-to-23000-for-2024-ira-limit-rises-to-7000

The maximum deferral to a 401k or other qualified plan is $23,000, or $30,500 if over age 50.  The maximum total contribution to a workplace plan (including employer match) is $76,500.

You can always contribute to a traditional IRA, however, if your income is over a specific limit, the contribution will not be deductible.  Making non-deductible contributions to a traditional IRA is not a major problem but it does place an extra burden on you to keep really good records, including some documents you need to keep for the rest of your life (not just 3 year as with most tax paperwork).  The ability to contribute to a Roth IRA depends on income.  The IRA deduction and Roth limits depend on filing status and whether you or your spouse participate in a workplace plan,  the are given at the first link above.  

In general, you should maximize your 401k match, if you have that option, since it's free money.  After that, the choice between adding more (non-matched funds) to the 401k, or making deductible and non-deductible IRA contributions, depends on so many factors that you really do need a book to think about them.