The footnotes for each chapter are listed at the end of the chapter.
There is a brief description of that poem in footnote 4 of chapter two.
The footnotes of the book are printed in a smaller font than the main text.
WordNet 3.0 Sense Numbers: 1
NOTE: a somewhat figurative extension of Sense 1
It has been said that all of western philosophy is but a footnote to Plato.
That battle was only a footnote in the context of the 100-year War.
It's a movement now regarded as just a footnote to modern architectural trends.
WordNet 0.0 Sense Numbers: 2a