Written Determinations
IRS Written Determinations are documents the IRS is required to make open to public inspection pursuant to the provisions of I.R.C. Sec. 6110. 
IRS Searchable list of Chief Counsel Advice (CCAs), Technical advice memoranda (TAMs), and Private Letter Rulings (PLRs) (1999 to date) available here on the IRS.gov site
Some selected PLRs related to 6166
Note: List non exhaustive
DT PLRs
PLR Link UILC Subject Release Date
201702004

2055.00-00

Transfers for Public, Charitable, and Religious Uses (Deductible v. Not Deductible)
201403012

6166.52-00

Acceleration of Estate Tax Payable in Installments
201403012

6166.50-00

Extension of Time For Payment of Estate Where Estate Consists Largely of Interest in Closely Held Business
201403012

6166.02-00

Acceleration of Payments
201403012

6166.00-00

Extension of Time to Pay Estate Tax
201343004

6166.00-00

Extension of Time to Pay Estate Tax
201015003

2032A.00-0

Valuation of Farm Real Property
201015003

2057.00-0

Qualified Family Business Interests
201015003

6166.00-00

Extension of Time to Pay Estate Tax
201015003

6651.00-00

Failure to File Tax Returns or Pay Tax (Addition v. No Addition to Tax)
200939003

6166.00-00

Extension of Time to Pay Estate Tax
200939003

2661.00-0

Administration
200842012

6166.03-00

Active Trade or Business
200842012

6166.00-00

Extension of Time to Pay Estate Tax
200613020

6166.00-00

Extension of Time to Pay Estate Tax
200613020

6166.02-00

Acceleration of Payments
200613020

6166.52-00

Acceleration of Estate Tax Payable in Installments
200529006

6166.00-00

Extension of Time to Pay Estate Tax
200339043

6166.00-00

Extension of Time to Pay Estate Tax
200339043

6166.03-00

Active Trade or Business
200321006

6166.00-00

Extension of Time to Pay Estate Tax
200321006

6166.02-00

Acceleration of Payments
200321006

6166.52-00

Acceleration of Estate Tax Payable in Installments
200043031

2013.00-00

Credit for tax on Prior transfers
200043031

6166.00-00

Extension of Time to Pay Estate Tax
200006034

6166.03-00

Active Trade or Business
199929025

6166.03-00

Active Trade or Business
8527003

6166.00-00

IRS formula for the secondary section 6166(k)(5) computation
8813047

6166.00-00

Code Secs. 303 and 6166
8846001

6166.00-00

Determination of the amount of a deficiency payable in installments
8846001-1

6166.00-00

Determination of the amount of a deficiency payable in installments - Computation Illustration I
8846001-2

6166.00-00

Interest is interrelated with the estate tax - Computation Illustration II
8846001-3

6166.00-00

The Estate's calculation of deferred tax and the annual installments payable - Computation Illustration III
8846001-4

6166.00-00

The IRS calculation of the deferred portion of the deficiency and the annual installments payable - Computation Illustration IV
6612073550A

6166.00-00

Extension of time for payment of estate tax where estate consists largely of interest in closely held business