EXHIBIT 99.6

GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
NUMBER ON SUBSTITUTE FORM W-9

GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION NUMBER TO GIVE THE
PAYER -- 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
proper identification number to give:

<Table>
<Caption>
- --------------------------------------------------------
GIVE THE NAME AND
SOCIAL SECURITY
FOR THIS TYPE OF ACCOUNT: NUMBER OF --
- --------------------------------------------------------

1. Individual account The individual
2. Two or more individuals The actual owner of the
(joint account) account or, if combined
funds, the first
individual on the
account(1)
3. Custodian account of a The minor(2)
minor (Uniform Gift to
Minors Act)
4. a. The usual revocable The grantor-trustee(1)
savings trust
(grantor is also
trustee)
b. The so-called trust The actual owner(1)
account that is not a
legal or valid trust
under state law
5. Sole proprietorship or The owner(3)
single-owner limited
liability company
</Table>

- ------------------------------------------------------

<Table>
<Caption>
- --------------------------------------------------------
GIVE THE NAME AND
EMPLOYER
IDENTIFICATION
FOR THIS TYPE OF ACCOUNT: NUMBER OF --
- --------------------------------------------------------

6. A valid trust estate, or Legal entity (do not
pension trust furnish the
identification number of
the personal
representative or
trustee unless the legal
entity itself is not
designated in the
account title)(4)
7. Corporation or limited The corporation
liability company
validly electing to be
taxed as a corporation
8. Association, club, The organization
religious, charitable,
educational, or other
tax-exempt organization
9. Partnership or multi- The partnership
member limited liability
company
10. A broker or registered The broker or nominee
nominee
11. Account with the The public entity
Department of
Agriculture in the name
of a public entity (such
as a State or local
government, school
district, or prison)
that receives
agricultural program
payments
</Table>

- ------------------------------------------------------

(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) You must show your individual name, but you may also enter your business or
"doing business as" name. You may use either your social security number or
employment identification number.
(4) List first and circle the name of the legal trust, estate or pension trust.

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

GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
NUMBER ON SUBSTITUTE FORM W-9

OBTAINING A NUMBER

If you do not have a taxpayer identification number or you do not know your
number, obtain Form SS-5, Application for a Social Security Number Card, or Form
SS-4, Application for Employer Identification Number, at the local office of the
Social Security Administration or the Internal Revenue Service and apply for a
number.

PAYEES EXEMPT FROM BACKUP WITHHOLDING

- An organization exempt from tax under section 501(a), or an individual
retirement plan, or a custodial account under Section 403(b)(7).

- The United States or any agency or instrumentality thereof.

- A state, the District of Columbia, a possession of the United States, or any
subdivision or instrumentality thereof.

- A foreign government, a political subdivision of a foreign government, or
any agency or instrumentality thereof.

- An international organization or any agency, or instrumentality thereof.

PAYEES THAT MAY BE EXEMPT FROM BACKUP WITHHOLDING:

- A corporation.

- A foreign central bank of issue.

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

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

- A real estate investment trust.

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

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

- A financial institution.

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

- 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 United
States and which have at least one nonresident alien partner.

- Payments made by certain foreign organizations.

- Payments of patronage dividends not paid in money.

- 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 the payer's trade or business and you have not provided
your correct taxpayer identification number to the payer.

- 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.

- Mortgage or student loan interest paid to you.

Exempt payees described above should file a Substitute Form W-9 to avoid
possible erroneous backup withholding.

FILE THIS FORM WITH THE PAYER, FURNISH YOUR TAXPAYER IDENTIFICATION NUMBER,
WRITE "EXEMPT" ON THE FACE OF THE FORM, SIGN AND DATE THE FORM AND RETURN IT TO
THE PAYER.

Payments that are not subject to information reporting are also not subject to
backup withholding. For details, see regulations under sections 6041, 6041A,
6042, 6044, 6045, 6049, 6050A, and 6050N.

PRIVACY ACT NOTICE. -- Section 6109 requires most recipients of dividends,
interest, or other payments to provide identifying number for identification
purposes and to help verify the accuracy of your return. Payers must be given
the numbers whether or not recipients are required to file tax returns. Payers
must generally withhold 28% (under current law) of taxable interest, dividends,
and certain other payments to a payee who does not furnish a taxpayer
identification number to a payer. Certain penalties may also apply.

PENALTIES.

(1) PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER. -- If you
fail to furnish your taxpayer identification number to a payer, 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. -- 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.

Form W-8BEN CERTIFICATE OF FOREIGN STATUS OF BENEFICIAL OWNER OMB No. 1545-1621
FOR UNITED STATES WITHHOLDING
(Rev. December 2000) - SECTION REFERENCES ARE TO THE INTERNAL REVENUE CODE.
- SEE SEPARATE INSTRUCTIONS.
Department of the - GIVE THIS FORM TO THE WITHHOLDING AGENT OR PAYER. DO NOT
Treasury SEND TO THE IRS.
Internal Revenue
Service
- ------------------------------------------------------------------------------------------------------------
</Table>

DO NOT USE THIS FORM FOR: INSTEAD, USE FORM:

<Table>

-- A U.S. citizen or other U.S. person, including a resident alien
individual............................................................W-9
-- A person claiming an exemption from U.S. withholding on income
effectively connected with the conduct of a trade or business in the
United States......................................................W-8ECI
-- A foreign partnership, a foreign simple trust, , or a foreign grantor
trust (see instructions for exceptions)..................W-8ECI or W-8IMY
-- A foreign government, international organization, foreign central bank of
issue, foreign tax exempt organization, foreign private foundation, or
government of a U.S. possession that received effectively connected
income or that is claiming the applicability of sections(s) 115(2),
501(c), 892, 895, or 1443(b) (see instructions)..........W-8ECI or W-8EXP
NOTE:These entities should use Form W-8BEN if they are claiming treaty
benefits or are providing the form only to claim they are a foreign
person exempt from backup withholding.
-- A person acting as an intermediary.................................W-8IMY
</Table>

NOTE: See instructions for additional exceptions.
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PART I IDENTIFICATION OF BENEFICIAL OWNER (See instructions.)
- --------------------------------------------------------------------------------

<Table>

1 Name of individual organization that is the beneficial owner 2 Country of incorporation or organization

- --------------------------------------------------------------------------------------------------------------------
</Table>
<Table>

3 Type of beneficial owner: [ ] Individual [ ] Corporation [ ] Disregarded [
entity ] Partnership

[ ] Grantor trust [ ] Complex trust [ ] Estate [ ] Government [
] International
organization

[ ] Central bank of issue [ ] Tax-exempt [ ] Private
organization foundation

3 [ ] Simple
trust
</Table>

<Table>

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4 Permanent residence address (street, apt. or suite no., or rural route). DO NOT USE A P.O. BOX OR IN-CARE-OF
ADDRESS.

- --------------------------------------------------------------------------------------------------------------------
City or town, state or province. Include postal code where Country (do not abbreviate)
appropriate.

- --------------------------------------------------------------------------------------------------------------------
5 Mailing address (if different from above)

- --------------------------------------------------------------------------------------------------------------------
</Table>

<Table>

6 U.S. taxpayer identification number, if required (see 7 Foreign tax identifying number, if any (optional)
instructions)
[ ] SSN or ITIN [ ] EIN
- ---------------------------------------------------------------------------------------------------------------------------
8 Reference number(s) (see instructions)

</Table>

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PART II CLAIM OF TAX TREATY BENEFITS (if applicable)
- --------------------------------------------------------------------------------

<Table>

9 I CERTIFY THAT (CHECK ALL THAT APPLY):
A [ ] The beneficial owner is a resident of ______________ within
the meaning of the income tax treaty between the United
States and that country.
B [ ] If required, the U.S. taxpayer identification number is
stated on line 6 (see instructions).
C [ ] The beneficial owner is not an individual, derives the item
(or items) of income for which the treaty benefits are
claimed, and, if applicable, meets the requirements of the
treaty provision dealing with limitation on benefits (see
instructions).
D [ ] The beneficial owner is not an individual, is claiming
treaty benefits for dividends received from a foreign
corporation or interest from a U.S. trade or business of a
foreign corporation, and meets qualified resident status
(see instructions).
E [ ] The beneficial owner is related to the person obligated to
pay the income within the meaning of section 267(b) or
707(b), and will file Form 8833 if the amount subject to
withholding received during a calendar year exceeds, in the
aggregate, $500,000.
10 SPECIAL RATES AND CONDITIONS (if applicable -- see
10 instructions): The beneficial owner is claiming the provisions of
Article ______________ of the treaty identified on line 9a above
to claim a ______________ % rate of withholding on (specify type
of income):
Explain the reasons the beneficial owner meets the terms of the
treaty article
</Table>

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PART III NOTIONAL PRINCIPAL CONTRACTS
- --------------------------------------------------------------------------------

<Table>

11 [ ] I have provided or will provide a statement that identifies
those notional principal contracts from which the income
isNOT effectively connected with the conduct of a trade or
business in the united states. I agree to update this
statement as required.
</Table>

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PART IV CERTIFICATION
- --------------------------------------------------------------------------------
Under penalties of perjury, I declare that I have examined the information on
this form and to the best of my knowledge and belief it is true, correct, and
complete. I further certify under penalties of perjury that:
-- I am the beneficial owner (or am authorized to sign for the beneficial
owner) of all the income to which this form relates,
-- The beneficial owner is not a U.S. person,
-- The income to which this form relates is not effectively connected with the
conduct of a trade or business in the United States or is effectively
connected but is not subject to tax under an income tax treaty, AND
-- For broker transactions or barter exchanges, the beneficial owner is an
exempt foreign person as defined in the instructions.
Furthermore, I authorize this form to be provided to any withholding agent that
has control, receipt, or custody of the income of which I am the beneficial
owner or any withholding agent that can disburse or make payments of the income
of which I am the beneficial owner.
<Table>

SIGN HERE - -----------------------------------------------------------
Signature of beneficial owner (or individual authorized to sign for beneficial owner)

SIGN HERE - ---------------- ------------------
Date (MM-DD-YYYY) Capacity in which acting
</Table>

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FOR PAPERWORK REDUCTION ACT NOTICE, SEE SEPARATE INSTRUCTIONS. Cat. No.
25047Z Form W-8BEN (Rev. 12-2000)