Are you "Smart"?

I found the reference to Shel Silverstein's very funny poem "Smart" in Thaler and Sunstein's Nudge (Yale University Press, 2008). They added an equally funny footnote. "Silverstein had personally given Thaler permission to use the poem in an academic paper published in 1985 . . . but the poem is now controlled by his estate, which, after several nudges (otherwise known as desperate pleas), has denied us permission to reprint the poem here. Since we would have been happy to pay royalties, unlike the Web sites you will find via Google, we can only guess that the managers of the estate (to paraphrase the poem) don't know that some is more than none." (p. 77)