From user@domain  Fri Feb 22 17:06:23 2008
Message-ID: <a@b>

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From user@domain  Fri Feb 22 15:06:23 2008
Message-Id: <b@b>
References: <a@b> <c@b>

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From user@domain  Fri Feb 22 16:06:25 2008
Message-Id: <c@b>
References: <b@b>

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