apparently-from
apparently-to
bcc
cc
content-description
content-disposition
content-length
content-transfer-encoding
content-type
date
expires
followup-to
from
in-reply-to
lines
list-post
mail-followup-to
mail-reply-to
message-id
mime-version
newsgroups
organization
received
references
reply-to
return-path
sender
status
subject
supercedes
supersedes
to
x-comment-to
x-label
xref
x-status