/To:s([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i

/To:s([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i
/To: ([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i
/To:[s]{0,2}([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i
/:s([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i

/s([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i

/([a-z0-9][-a-z0-9]{1,19})@somedomain.com[a-z0-9s=;:/.-]*1b/i

Subject: Test spam mail (GTUBE) private jet rental
Message-ID: <GTUBE1.1010101@example.net>
Date: Wed, 23 Jul 2003 23:30:00 +0200
From: Sender <sender@live.com>
To: recipient@somedomain.com
Precedence: junk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
recipient
This is the GTUBE, the
    Generic
    Test for
    Unsolicited
    Bulk
    Email