[MSDN Library June 1998] MTE Per-Message Properties (100%)
MSDN Library Visual Studio 6.0 > Platform SDK > Database and Messaging Services > Microsoft Exchange Server > Gateway Programmer's Reference > Guide > Message Transfer > Using Message Transfer Envelope Properties
[MSDN Library June 1998] MTE Per-Recipient Properties (93.75%)
MSDN Library Visual Studio 6.0 > Platform SDK > Database and Messaging Services > Microsoft Exchange Server > Gateway Programmer's Reference > Guide > Message Transfer > Using Message Transfer Envelope Properties