MooKu SG You can try the Esplanade library, but you'll need a premium library membership to borrow the scores. I don't know if they have "The Riddle", but I found another song there before.
MooKu SG If you mean BUY online, yes of course! One song is about USD$4. Otherwise, sorry I don't know.
HygieneSetsco SG hmm, quite a nice site, but doesn't have the riddle. anyone else has any good sites?