Original indexer credited Frank Giacoia as cover co-penciler.
According to Roy Thomas, Larry Lieber plotted,(likely) dialogued and pencilled approximately the first half of the story when he had to bow out. Roy plotted and wrote the second half, with Frank Giacoia penciling. It appears that Lieber wrote and drew pages 1-11; with Thomas scripting and Giacoia penciling pages 12-24. Info per Nick Caputo, March 2013.
The previous appearance of Dr. Doom was in Strange Tales (Marvel, 1951 series #167) and his next appearance is in Fantastic Four (Marvel, 1961 series) #84.
The Torch's last appearance was in Marvel Mystery Comics #92 (June 1949).
In revisionist history, intro Captain America IV and Bucky III
previous appearance of Captain America was in Captain America's Weird Tales (Marvel, 1949 series) #74.
last Sub-Mariner appearance was in Marvel Mystery Comics #92 (June 1949)