http://basementgeographer.com/reclaimed-land-in-singapore-nation-building-in-the-most-literal-sense/
https://books.google.com.sg/books?id=iPDP4K0AnA4C&pg=PA204&lpg=PA204&dq=what+materials+have+singapore+used+for+land+reclamation&source=bl&ots=ScpMEyQ86F&sig=nMtR5jxdXD3kO1NPhUKgmllcz-g&hl=en&sa=X&ei=eQX_VI-TBs-hugSbx4DgDg&ved=0CFkQ6AEwCQ#v=onepage&q=what%20materials%20have%20singapore%20used%20for%20land%20reclamation&f=false
http://foodbank.sg/index.php/the-big-issues/food-wastage-in-singapore