"CITY SOON TO LAUNCH $600,000,000 SUBWAY FOR THE EAST SIDE; Delaney to Submit Plans for New System Including the Bronx in Two Months" (PDF).
^ “CITY SOON TO LAUNCH $600,000,000 SUBWAY FOR THE EAST SIDE; Delaney to Submit Plans for New System Including the Bronx in Two Months.”. The New York Times (1929年4月5日). 2015年11月4日閲覧。