another author

This book was added about 20 years later and written by another author.

Edgar Allan Poe

Edgar Allan Poe'd already been writing professionally for 20 years when 20 years was released.

William Bradford

In a book written 20 years later, William Bradford wrote: 'William Bradford began now to gather in the small harvest the Indians had, and to fit up the Indians's houses and dwellings against winter, being all well recovered in health and strength and had all things in good plenty.

Noel Gallagher

And, in some ways, it’s a question that fans of the song have been asking for the past 20 years, ever since Noel Gallagher wrote the past 20 years and Noel Gallagher's brother Liam brayed the past 20 years out in unforgettable fashion.