
                                                            Exhibit 99(a)(1)(vi)

                   GUIDELINES FOR CERTIFICATION OF TAXPAYER ID

             GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION

                          NUMBER ON SUBSTITUTE FORM W-9

              GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION
                            NUMBER TO GIVE THE PAYOR.

            Social Security numbers have nine digits separated by two hyphens:
i.e., 000-00-0000. Employer identification numbers have nine digits separated by
only one hyphen: i.e., 00-0000000. The table below will help determine the
number to give the payor.

FOR THIS TYPE OF ACCOUNT:                     GIVE THE NAME AND TAXPAYER
                                              IDENTIFICATION NUMBER:

1.  An individual's account                   The individual

2.  Two or more individuals (joint account)   The actual owner of account or,
                                              if combined funds, any one of the
                                              individuals (1)

3.  Custodian account of a minor (Uniform     The minor (2)
    Gift to Minors Act)

4.  a. The usual revocable savings trust      The grantor- trustee (1)
    account (grantor is also trustee)

    b. So-called trust account that is not a
    legal or valid trust under state law      The actual owner (1)

5.  Sole proprietorship account or single-
    owner LLC                                 The owner (3)

                                              GIVE THE NAME AND EMPLOYEE
FOR THIS TYPE OF ACCOUNT                      IDENTIFICATION NUMBER

6.  A valid trust, estate, or pension trust   The legal entity

7.  Corporate account                         The corporation

8.  Association, club, religious,             The organization
    charitable, educational or other
    tax-exempt organization

9.  Partnership account or multi-member LLC   The partnership or LLC

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10. A broker or registered nominee            The broker or nominee

11. Account with the Department of            The public entity
    Agriculture in the name of a public
    entity (such as a state or local
    government, school district, or prison)
    that receives agricultural program
    payments

(1) List first and circle the name of the person whose number you furnish. If
only one person on a joint account has a Social Security number, that person's
number must be furnished.

(2) Circle the minor's name and furnish the minor's social security number.

(3) Show the name of the owner. Owner may use either owner's social security
number or owner's employer identification number.

(4) List first and circle the name of the legal trust, estate or pension trust.
(Do not furnish identifying number of the personal representative or trustee
unless the legal entity itself is not designated in the account title.)

      NOTE:       If no name is circled when more than one name is listed, the
                  number will be considered to be that of the first name listed.

RESIDENT ALIEN INDIVIDUALS: If you are a resident alien individual and you do
not have, and are not eligible to get, a Social Security number, your taxpayer
identification number is your individual taxpayer identification number ("ITIN")
as issued by the Internal Revenue Service. Enter it on the portion of the
Substitute Form W-9 where the Social Security number would otherwise be entered.
If you do not have an ITIN, see "Obtaining a Number" below.

NAME:

            If you are an individual, generally provide the name shown on your
social security card. However, if you have changed your last name, for instance,
due to marriage, without informing the Social Security Administration of the
name change, please enter your first name and both the last name shown on your
social security card and your new last name.

OBTAINING A NUMBER:

            If you do not have a taxpayer identification number, obtain Form
SS-5, Application for a Social Security Number Card (for individuals), or Form
SS-4, Application for Employer Identification Number (for businesses and all
other entities), at the local office of the Social Security Administration or
the Internal Revenue Service (the "IRS") and apply for a number. Resident alien

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individuals who are not eligible to get a Social Security number and need an
ITIN should obtain Form W-7, Application for Individual Taxpayer Identification
Number, from the IRS.

PAYEES AND PAYMENTS EXEMPT FROM BACKUP WITHHOLDING:

            The following is a list of payees exempt from backup withholding and
for which no information reporting is required. For interest and dividends, all
listed payees are exempt except the payee in item (9). For broker transactions,
payees listed in items (1) through (13) and a person registered under the
Investment Advisers Act of 1940 who regularly acts as a broker are exempt.
Payments subject to reporting under sections 6041 and 6041A are generally exempt
from backup withholding only if made to payees described in items (1) through
(7). Unless otherwise indicated, all "section" references are to sections of the
Internal Revenue Code of 1986, as amended (the "Code").

      1.    A corporation.

      2.    An organization exempt from tax under section 501(a), or an IRA, or
            a custodial account under section 403(b)(7) if the account satisfies
            the requirements of section 401(f)(2).

      3.    The United States or any of its agencies or instrumentalities.

      4.    A state, the District of Columbia, a possession of the United
            States, or any of their political subdivisions or instrumentalities.

      5.    A foreign government or any of its political subdivisions, agencies
            or instrumentalities.

      6.    An international organization or any of its agencies or
            instrumentalities.

      7.    A foreign central bank of issue.

      8.    A dealer in securities or commodities required to register in the
            United States, the District of Columbia, or a possession of the
            United States.

      9.    A futures commission merchant registered with the Commodity Futures
            Trading Commission.

      10.   A real estate investment trust.

      11.   An entity registered at all times during the tax year under the
            Investment Company Act of 1940.

      12.   A common trust fund operated by a bank under section 584(a).

      13.   A financial institution.

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      14.   A middleman known in the investment community as a nominee or
            custodian.

      15.   A trust exempt from tax under section 664 or described in section
            4947.

PAYMENTS OF DIVIDENDS AND PATRONAGE DIVIDENDS NOT GENERALLY SUBJECT TO BACKUP
WITHHOLDING INCLUDE THE FOLLOWING:

      -     Payments to nonresident aliens subject to withholding under section
            1441.

      -     Payments to partnerships not engaged in a trade or business in the
            U.S. and which have at least one nonresident partner.

      -     Payments of patronage dividends where the amount received is not
            paid in money.

      -     Payments made by certain foreign organizations.

      -     Section 404(k) distributions made by an ESOP.

PAYMENTS OF INTEREST NOT GENERALLY SUBJECT TO BACKUP WITHHOLDING INCLUDE THE
FOLLOWING:

      -     Payments of interest on obligations issued by individuals. Note: You
            may be subject to backup withholding if this interest is $600 or
            more and is paid in the course of your trade or business and you
            have not provided your correct taxpayer identification number to the
            payor.

      -     Payments of tax-exempt interest (including exempt-interest dividends
            under section 852).

      -     Payments described in section 6049(b)(5) to non-resident aliens.

      -     Payments on tax-free covenant bonds under section 1451.

      -     Payments made by certain foreign organizations.

      -     Payments of mortgage or student loan interest to you.

            Exempt payees described above should file Substitute Form W-9 to
avoid possible erroneous backup withholding. FILE THIS FORM WITH THE PAYOR;
FURNISH YOUR TAXPAYER IDENTIFICATION NUMBER; WRITE "EXEMPT" ON THE FACE OF THE
FORM, SIGN AND DATE THE FORM AND RETURN IT TO THE PAYOR. IF YOU ARE A
NON-RESIDENT ALIEN OR A FOREIGN ENTITY NOT SUBJECT TO BACKUP WITHHOLDING, FILE
WITH PAYOR THE APPROPRIATE COMPLETED INTERNAL REVENUE SERVICE FORM W-8.

            Certain payments other than interest, dividends and patronage
dividends, that are not subject to information reporting are also not subject to
backup withholding. For details, see Sections 6041, 6041A, 6042, 6044, 6045,
6049, 6050A and 6050N of the Code and the Treasury regulations promulgated
thereunder.

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PRIVACY ACT NOTICE -- Section 6109 requires most recipients of dividend,
interest, or other payments to give their correct taxpayer identification
numbers to payors who must report the payments to the IRS. The IRS uses the
numbers for identification purposes and to verify the accuracy of tax returns.
The IRS also may provide this information to the Department of Justice for civil
and criminal litigation and to cities, states, and the District of Columbia to
carry out their tax laws. Payors must be given the numbers whether or not
recipients are required to file tax returns. Payors must generally withhold tax
from payments of taxable interest, dividend, and certain other payments to a
payee who does not furnish a taxpayer identification number to a payor. The
current rate of such withholding tax is 28%. Certain penalties may also apply.

PENALTIES

      1.    PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER -- If
            you fail to furnish your correct taxpayer identification number to a
            payor, you are subject to a penalty of $50 for each such failure
            unless your failure is due to reasonable cause and not to willful
            neglect.

      2.    CIVIL PENALTY FOR FALSE INFORMATION WITH RESPECT TO WITHHOLDING --
            If you make a false statement with no reasonable basis which results
            in no imposition of backup withholding, you are subject to a penalty
            of $500.

      3.    CRIMINAL PENALTY FOR FALSIFYING INFORMATION -- Willfully falsifying
            certifications or affirmations may subject you to criminal penalties
            including fines and/or imprisonment.

FOR ADDITIONAL INFORMATION CONTACT YOUR TAX CONSULTANT OR THE INTERNAL REVENUE
SERVICE.

