Original sentence: By contract dated July 1, 1926 (in the NBC History Files at the Library of Congress), AT&T sold the assets of BCA, principally WEAF, but also the Washington, DC station WCAP, to RCA for $1 million
Edited sentence: By a contract dated July 1, 1926 (in the NBC History Files at the Library of Congress), AT&T sold the assets of BCA, principally WEAF, but also the Washington, DC station WCAP, to RCA for $1 million