AIGA article about the signage history of the NYC subway system:
"There is a commonly held belief that Helvetica is the signage typeface of the New York City subway system ... it is only somewhat true ... this essay explores several important histories: of the New York City subway system, transportation signage in the 1960s, Unimark International and, of course, Helvetica. These four strands are woven together, over nine pages, to tell a story that ultimately transcends the simple issue of Helvetica and the subway."
