I learned to say it from a piece many years ago (before SSiW) on WRI - Wales Radio International. I downloaded the piece to my computer all those years ago so I have it if someone wants it (mp3 format). But I searched for it online and found a lot of (old) links to the original story which, however, has apparently disappeared.
EDIT: I’ve uploaded the track to Soundcloud. It is a bit more than 5 minutes long; and here it is: