(1980). Surficial geologic map of the Worcester North quadrangle and part of the Paxton quadrangle, Worcester county, Massachusetts. U.S. Geological Survey.
Chicago-Zitierstil (17. Ausg.)Surficial Geologic Map of the Worcester North Quadrangle and Part of the Paxton Quadrangle, Worcester County, Massachusetts. Reston: U.S. Geological Survey, 1980.
MLA-Zitierstil (9. Ausg.)Surficial Geologic Map of the Worcester North Quadrangle and Part of the Paxton Quadrangle, Worcester County, Massachusetts. U.S. Geological Survey, 1980.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.