"The Workers – Dutch". The Thai-Burma Railway & Hellfire Pass. Department of Veterans Affairs – Australia. 2014. Archived from the original on 27 January 2014. Retrieved 21 January 2014.
"Banno Hirateru and others". Singapore War Crimes Trials. Retrieved 1 February 2022. Trial was for F-force which lost 3,000 out of 7,000 men. Sonkrai was a part of F-force
"Search For War Dead". Commonwealth War Graves Commission. 2012. Archived from the original on 7 August 2012. Retrieved 1 August 2012.
"The Workers – Dutch". The Thai-Burma Railway & Hellfire Pass. Department of Veterans Affairs – Australia. 2014. Archived from the original on 27 January 2014. Retrieved 21 January 2014.