43 sources
The Brave and the Bold
Captain America (vol. 1) #256 (Apr. 1981): "The Ghosts of Greymoor Castle!"
Dazzler #2 (Apr. 1981): "Where Demons Fear to Dwell!"
The Defenders (vol. 1) #94 (Apr. 1981): "Beware--The Six-Fingered Hand!"
Doctor Strange
The Evil Dead (1981)
Ghost Rider (vol. 2) #55 (Apr. 1981): "Touch of Terror"
The Greatest American Hero
Green Lantern
The Incredible Hulk (vol. 2) #258 (Apr. 1981): "To Hunt the Hulk!"
Justice League of America (vol. 1) #189 (Apr. 1981): "The Return of the Starfish Conquerer!"
Ka-Zar the Savage #1 (Apr. 1981): "A New Dawn... a New World!"
Legion of Super-Heroes (vol. 2) #274 (Apr. 1981): "The Exaggerated Death of Ultra Boy"
Marvel Premiere
Marvel Team-Up (vol. 1) #104 (Apr. 1981): "Ka-Zar is King!"
Marvel Two-in-One (vol. 1) #74 (Apr. 1981): "A Christmas Peril!"
Master of Kung Fu #99 (Apr. 1981): "Bitter Harvest"
The Micronauts (vol. 1) #28 (Apr. 1981): "...Last Stand in Fantasy-World!"
Moon Knight (vol. 1) #6 (Apr. 1981): "White Angels"
The New Adventures of Superboy
The New Teen Titans (vol. 1) #6 (Apr. 1981): "Last Kill!"
Peter Parker, The Spectacular Spider-Man #53 (Apr. 1981): "Toys of the Terrible Tinkerer"
ROM #17 (Apr. 1981): "Hybrid!"
The Savage She-Hulk #15 (Apr. 1981): "Delusions"
Spider-Woman (vol. 1) #37 (Apr. 1981): "Who Am I?"
Thor
The Uncanny X-Men (vol. 1) #144 (Apr. 1981): "Even In Death..."
The Warlord
What If?