Beard, Ithamar A, J Hoar, and George W. Boynton. Map of the city of Lowell: surveyed by order of the municipal authorities. Boston: I.A. Beard, 1841. Map. Library of Congress Geography and Map Division Washington, D.C.
Beard, Hoar, G.W. Boynton & Co., & Hoar, J. (1842). Map of the city of Lowell : surveyed in 1841 by order of the municipal authorities [Map]. I.A. Beard. Harvard University, Harvard Map Collection.
