แม่แบบ:R:gem:Kortlandt:1992
Kortlandt, Frederik (1992), chapter The Germanic fifth class of strong verbs, in North-Western European Language Evolution (NOWELE), volume 19, issue 1, pages 101–107
Kortlandt, Frederik (1992), chapter The Germanic fifth class of strong verbs, in North-Western European Language Evolution (NOWELE), volume 19, issue 1, pages 101–107