Which is the Smallest Planet?

From Author Wars - https://authorwars.com/books/which-is-the-smallest-planet-2498805.html

Overview:

Title: Which is the Smallest Planet?
Author: uncredited
Year: 1979
Type: Essays

Editions/Publications:

Unknown. Doctor Who Annual 1980 (Unknown, uncredited, World Distributors, ISBN-10: 072356549X, £1.75, 61 pages, Hardcover, Anthology)
Unknown. Doctor Who Annual 1980 (Unknown, uncredited, World Distributors, ISBN-10: 072356549X, 61 pages, Hardcover, Anthology)