Historical clue formulations

• Mail order abbr. — 2014-11-12
• One way to send merchandise: Abbr. — 2003-09-28
• Mail order abbr. — 2001-01-23
• How most goods must be ordered by mail: Abbr. — 1998-07-15
• Mail-order abbr. — 1997-06-21
• Shipment notation: Abbr. — 1997-01-11
• Shipping letters — 1994-08-25
• Mail-order abbr. — 1994-05-15
• Abbr. in a mail-order ad — 1994-03-14