WITNESSETH THAT:

                                                                     Exhibit 4.b

                                                             Executed in 6 Parts
                                                             Counterpart No. ( )

                              NATIONAL EQUITY TRUST

             SHORT-TERM LOW FIVE COVERED WRITE OPTION TRUST SERIES 4

                            REFERENCE TRUST AGREEMENT

      This Reference Trust Agreement dated May 8, 2002 among Prudential
Investment Management Services LLC, as Depositor, Prudential Securities
Incorporated, as Portfolio Supervisor, and The Bank of New York, as Trustee,
sets forth certain provisions in full and incorporates other provisions by
reference to the document entitled "National Equity Trust, Trust Indenture and
Agreement" (the "Basic Agreement") dated August 8, 2001. Such provisions as are
set forth in full herein and such provisions as are incorporated by reference
constitute a single instrument (the "Indenture").

                                WITNESSETH THAT:

      In consideration of the premises and of the mutual agreements herein
contained, the Depositor and the Trustee agree as follows:

                                     Part I.

                     STANDARD TERMS AND CONDITIONS OF TRUST

      Subject to the provisions of Part II hereof, all the provisions contained
in the Basic Agreement are herein incorporated by reference in their entirety
and shall be deemed to be a part of this instrument as fully and to the same
extent as though said provisions had been set forth in full in this instrument.

      (i) The first sentence of Section 9.05 - Written Notice shall be amended
by deleting the language "Prudential Securities Incorporated at Xxx Xxxxxxx
Xxxxx, Xxx Xxxx, Xxx Xxxx 00000" and replacing it with "Prudential Investment
Management LLC at 000 Xxxxxxxx Xxxxxx, Xxxxxxx Center Three, Xxxxxx, Xxx Xxxxxx
00000".


                                      -2-


                                     Part II

                      SPECIAL TERMS AND CONDITIONS OF TRUST

      The following special terms and conditions are hereby agreed to:

      A. The Trust is denominated National Equity Trust, Short-Term Low Five
Covered Write Option Trust Series 4.

      B. The publicly traded stocks listed in Schedule A hereto are those which,
subject to the terms of this Indenture, have been or are to be deposited in
Trust under this Indenture as of the date hereof subject to the Purchase Rights
listed in Schedule A hereto.

      C. The term "Depositor" shall mean Prudential Investment Management
Services LLC.

      D. The term "Portfolio Supervisor" shall mean Prudential Securities
Incorporated.

      E. The aggregate number of Units referred to in Sections 2.03 and 9.01 of
the Basic Agreement is 5,052,860 as of the date hereof.

      F. A Unit of the Trust is hereby declared initially equal to 1/5,052,860th
of the Trust.

      G. The term "First Settlement Date" shall mean May 14, 2002.

      H. The term "Distribution Date" shall be as soon as possible after the
Termination Date to Unit Holders of record on the Termination Date.

      I. The term "Termination Date" shall mean Decmeber 4, 2002.

      J. The Trustee's Annual Fee shall be $1.10 (per 1,000 Units).

      K. The Portfolio Supervisor's portfolio supervisory service fee shall be
$.25 per 1,000 Units.

               [Signatures and acknowledgments on separate pages]


                                      -3-


The Schedule of Portfolio Securities in Part A of the prospectus included in
this Registration Statement for National Equity Trust, Short-Term Low Five
Covered Write Option Trust Series 4 is hereby incorporated by reference herein
as Schedule A hereto.