Part 1 of the original story.
Indicia on page 1 lists:
Copyright 1975 Marvel Comics International Ltd. All rights reserved. Based on material copyright 1971 by Magazine Management Co., Inc., Marvel Comics Group, and copyright 1968 by Olympia Publications, Inc. Marvel Comics Group and copyright 1967 by Canam Publishers Sales Group. Marvel Comics Group, Hulk, The Defenders, Daredevil, and Fantastic Four are Tradenames and Trademarks of the Marvel Comics Group, a division of Cadence Industries Corp., N.Y., N.Y., USA. Edited by Matt Softley. Not to be sold in the United States of America or Canada. Member of ABC. Printed in Ireland by Lithograohic Universal (Export) Ltd., Dublin -- London office, 40 Buckingham Palace Road, London SW1W ORE, Tel. 01-828-0261.
Per Jean Baptiste Leblanc, Vince Colletta is credited as inker in the comic book but the inking may actually have been done by Dan Adkins, based on an examination of the art (August 16, 2006). Adkins credit confirmed in Marvelmania # 2. Information per Nick Caputo, June 2012.
Second half of the original story.
Kirby co-plot credit was acknowledged by Lee and Kirby in several interviews. The credit here read "Another titanic thrill-fest by Smilin' Stan Lee and Jolly Jack Kirby"
First half of original story.