And it was Peter Yarrow, not Paul Stookey, who co-wrote "Puff," based on a 1959 poem by Leonard Lipton.

Wikipedia on Puff, The Magic Dragon

[[Leonard Lipton, a 19-year-old Cornell University student ... was inspired by an Ogden Nash poem titled "Custard the Dragon," about a "realio, trulio little pet dragon."
Lipton was friends with Peter Yarrow's housemate when they were all students at Cornell. He used Yarrow's typewriter to get the poem out of his head. He then forgot about it until years later, when a friend called and told him Yarrow was looking for him, to give him credit for the lyrics. On making contact Yarrow gave Lipton half the songwriting credit, and he still gets royalties from the song.]]