"Circle Line Art"(PDF). lta.gov.sg. Archived from the original(PDF) on 11 February 2017. Retrieved 20 September 2020.
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Leong 2003, p. 31. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 107. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 102. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 100. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 105–107. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 210. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 94. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 248. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.
Leong 2003, p. 149. Leong, Chan Teik (2003). Getting there : The story of the North East Line. Singapore: Land Transport Authority. ISBN981-04-5886-X. OCLC53383062.