"Procurement Authorization Amendment - option to purchase 31 additional new subway train sets (for H6 subway car replacement and TYSSE)" (PDF).
2012년 1월 8일에 확인함.  “조달 지침 개정 - H6 열차 교체를 위한 31편성의 신차 구매 방안 (PROCUREMENT AUTHORIZATION AMENDMENT – OPTION TO PURCHASE 31 ADDITIONAL NEW SUBWAY TRAIN SETS (FOR H6 SUBWAY CAR REPLACEMENT AND TYSSE))” (PDF).