Joshi, Yugal Kishore; Tortajada, Cecilia; Biswas, Asit K. (2012). Cleaning of the Singapore River and Kallang Basin in Singapore: Human and Environmental Dimensions. AMBIO. 41 (7): 777—781. doi:10.1007/s13280-012-0279-0. ISSN0044-7447.(англ.)
Joshi, Yugal Kishore; Tortajada, Cecilia; Biswas, Asit K. (2012). Cleaning of the Singapore River and Kallang Basin in Singapore: Human and Environmental Dimensions. AMBIO. 41 (7): 777—781. doi:10.1007/s13280-012-0279-0. ISSN0044-7447.(англ.)