At the Earth's Core

From Author Wars - https://authorwars.com/publications/at-the-earths-core-248474.html

Overview:

Title: At the Earth's Core
Author: Edgar Rice Burroughs
Year: 1973
Publisher: Ace Books
Price: $1.25
Pages: 159
Binding: Paperback
Type: Novel
Title Reference: At the Earth's Core
Notes: Artist not credited, http://www.erbzine.com/mag7/0741.html says Frazetta, looks like his style. Art cards produced by Comic Images include this image in the Frazetta collection as #57. No printing date given. Ad at end if 15G, for ERB books with individual prices around $0.95. Date is from Robert B. Zeuschner's Edgar Rice Burroughs: The Bibliography which lists this as the sixth Ace printing and confirms the Frazetta cover.