------------------------------- Zitat Anfang -------------------------------

authentic   =   "From"       ":"   mailbox  ; Single author
            / ( "Sender"     ":"   mailbox  ; Actual submittor
                "From"       ":" 1#mailbox) ; Multiple authors
                                            ;  or not sender
mailbox     =  addr-spec                    ; simple address
            /  phrase route-addr            ; name & addr-spec
phrase      =  1*word                       ; Sequence of words
route-addr  =  "<" [route] addr-spec ">"
route       =  1#("@" domain) ":"           ; path-relative
addr-spec   =  local-part "@" domain
local-part  =  word *("." word)
word        =  atom / quoted-string
domain      =  sub-domain *("." sub-domain)
sub-domain  =  domain-ref / domain-literal
domain-ref  =  atom
atom        =  1*<any CHAR except specials, SPACE and CTLs>
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

CHAR        =  <any ASCII character>        ; (  0-177,  0.-127.)
                ^^^^^^^^^^^^^^^^^^^              oktal   decimal
                This means 7 bit ASCII -
                all national chars are coded above this range.
                Those chars must be coded with MIME as Quoted-printable.

specials    =  "(" / ")" / "<" / ">" / "@"       ; Must be in quoted-
                 /  "," / ";" / ":" / "\" / <">  ;  string, to use
                 /  "." / "[" / "]"              ;  within a word.
                                                   ^^^^^^^^^^^^^^^^^^

SPACE       =  <ASCII SP, space>            ; (     40,      32.)
CTL         =  <any ASCII control           ; (  0- 37,  0.- 31.)
                character and DEL>          ; (    177,     127.)
quoted-string = <"> *(qtext/quoted-pair) <">; Regular qtext or quoted-pair
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

qtext       =  <any CHAR excepting <">,     ; => may be folded
                "\" & CR, and including
                linear-white-space>
quoted-pair =  "\" CHAR                     ; may quote any char
domain-literal =  "[" *(dtext / quoted-pair) "]"

------------------------------- Zitat Ende ---------------------------------