"Kang Ding Qing Ge": what's the story?

I bought an electronic keyboard that has 100 songs stored in its memory. “Kang Ding Qing Ge”–identified by Chinese characters and this Pinyin spelling–is included. I’ve played it, and it’s a real nice melody, probably an old Chinese folk song. But the manual says nothing about the songs, and the sheet music doesn’t include this Chinese song, among others, because of “copyright restrictions.”
Do any Dopers know sopmething about this song, such as its history, composer (if known), and what music books might have the sheet music? Thanks very much.

Here are the lyrics, and a Google search has it listed in MP3 format. I haven’t found a free Chinese-English translator on the Web, though.