Riddle of the sphinx: Greek help needed

[sgarciab@soluziona.com]

Please excuse me this off-topic:

Any of you Greek members would help me to find out the original
ancient-greek text for the celebrated riddle of the sphynx ("What is that
which has one voice and yet becomes four-footed and two-footed and
three-footed?" [Apollodorus, Library 3.5.7])

Thanks in advance.

Santiago.