The Collaborative International Dictionary of English v.0.48:

Jahvist \Jah"vist\, n., Jahvistic \Jah*vis"tic\, a.
   See Jehovist, Jehovistic.
   [Webster 1913 Suppl.] Jahweh

The Collaborative International Dictionary of English v.0.48:

Yahwist \Yah"wist\, n. Also Jahvist \Jah"vist\, Jahwist
\Jah"wist\, older Jehovist \Je*ho"vist\
   The author of the passages of the Old Testament, esp. those
   of the Hexateuch, in which God is styled Yahweh, or Jehovah;
   the author of the Yahwistic, or Jehovistic, Prophetic
   Document (J); also, the document itself.
   [Webster 1913 Suppl.]