A "poem" purportedly written by a teenage Bob Dylan and up for auction at Christie's is actually a song written by the late Canadian country singer Hank Snow, the auction house said on Wednesday. Christie's announced on Tuesday the sale of the hand-written poem believed to have been written in 1957 when Dylan was 16 and away at Jewish camp. But Christie's failed to detect that the words, with a few minor variations, matched those of a song previously recorded by Snow, who died in 1999 at age 85.