This article discusses the history of the Maine Constitution, Maine being one of only nineteen states that have retained their original charter. The 158 amendments to the constitution are reviewed.
Palmer, Kenneth T., and Marcus LiBrizzi. "Development of the Maine Constitution: The Long Tradition, 1819-1988." Maine History 28, 3 (1989): 126-145. https://digitalcommons.library.umaine.edu/mainehistoryjournal/vol28/iss3/2