Gras, N. S. B. (1918). The early english customs system: A documentary study of the institutional and economic history of the customs from the thirteenth to the sixteenth century. Harvard Univ. Press.
Chicago-Zitierstil (17. Ausg.)Gras, Norman Scott Brien. The Early English Customs System: A Documentary Study of the Institutional and Economic History of the Customs from the Thirteenth to the Sixteenth Century. Cambridge: Harvard Univ. Press, 1918.
MLA-Zitierstil (9. Ausg.)Gras, Norman Scott Brien. The Early English Customs System: A Documentary Study of the Institutional and Economic History of the Customs from the Thirteenth to the Sixteenth Century. Harvard Univ. Press, 1918.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.