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 number to
give the payer.
 

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

                             GIVE THE
FOR THIS TYPE OF ACCOUNT:    SOCIAL SECURITY
                             NUMBER OF--
- ---------------------------------------------
                          
 1. An individual's account  The individual
 2. Two or more individuals  The actual owner
    (joint account)          of the 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-
   savings trust account     trustee(1)
   (grantor is also
   trustee)
b. So-called trust account   The actual owner
   that is not a legal or    (1)
   valid trust under State
   law
 5. Sole proprietorship      The owner(3)
    account
- ---------------------------------------------


                                        ------

                             GIVE THE EMPLOYER
FOR THIS TYPE OF ACCOUNT:    IDENTIFICATION
                             NUMBER OF--
                                        ------
                          
 6. Sole proprietorship      The owner
    account
 7. A valid trust, estate,   The legal entity
    or pension trust         (Do not furnish
                             the identifying
                             number of the
                             personal
                             representative
                             or trustee
                             unless the legal
                             entity itself is
                             not designated
                             in the account
                             title.)(4)
 8. Corporate account        The corporation
 9. Partnership account      The partnership
    held in the name of
    the business
10. Association, club,       The organization
    religious, charitable,
    or other tax-exempt
    organization
11. A broker or registered   The broker or
    nominee                  nominee
12. Account with the         The public
    Department of            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.
(2) Circle the minor's name and furnish the minor's social security number.
(3) Show the name of the owner. The name of the business or the "doing
    business as" name may also be entered. Either the social security number
    or the employer identification number may be used.
(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 OF SUBSTITUTE FORM W-9
                                    PAGE 2
OBTAINING A NUMBER
If you don't have a taxpayer identification number ("TIN") or you don't 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
Payees specifically exempted from backup withholding on all dividend and
interest payments and on broker transactions include the following:
 
 . A corporation.
 . A financial institution.
 . An organization exempt from tax under section 501(a), or an individual re-
   tirement plan, or a custodian 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.
 . A registered dealer in securities or commodities registered in the U.S. or
   a possession of the U.S.
 . A real estate investment trust.
 . A common trust fund operated by a bank under section 584(a).
 . An exempt charitable remainder trust, or a non-exempt trust described in
   section 4947(a)(1).
 . An entity registered at all times under the Investment Company Act of
   1940.
 . A foreign central bank of issue.
 
Payments of dividends and patronage dividends not generally subject to backup
withholding including 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.
 . Payments made to a nominee.
 
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 pro-
   vided 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 nonresident aliens.
 . Payments on tax-free covenant bonds under section 1451.
 . Payments made by certain foreign organizations.
 . Payments made to a nominee.
 
Exempt payees described above should file the Substitute Form W-9 to avoid
possible erroneous backup withholding. Complete the Substitute Form W-9 as
follows:
 
ENTER YOUR TAXPAYER IDENTIFICATION NUMBER, WRITE "EXEMPT" ACROSS THE FACE OF
THE FORM, SIGN, DATE, AND RETURN THE FORM TO THE PAYER.
 
 Certain payments other than interest, dividends, and patronage dividends that
are not subject to information reporting are also not subject to backup with-
holding. For details, see the sections 6041, 6041A(a), 6042, 6044, 6045, 6049,
6050A and 6050N and the regulations thereunder.
 
PRIVACY ACT NOTICE.--Section 6109 requires most recipients of dividend,
interest, or other payments to give taxpayer identification numbers to payers
who must report the payments to IRS. IRS uses the numbers for identification
purposes and to help verify the accuracy of tax reforms. Payers must be given
the numbers whether or not recipients are required to file tax returns. Payers
must generally withhold 31% of taxable interest, dividend, 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 correct 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.--Willfully falsifying
certifications or affirmations may subject you to criminal penalties including
fines and/or imprisonment.
(4) MISUSE OF TAXPAYER IDENTIFICATION NUMBERS.--If the payer discloses or uses
taxpayer identification numbers in violation of Federal law, the payer may be
subject to civil and criminal penalties.
 
FOR ADDITIONAL INFORMATION CONTACT YOUR TAX CONSULTANT OR THE INTERNAL REVENUE
SERVICE.