50 sources
The Adventures of Superman (vol. 1) #573 (Dec. 1999): "Higher Ground"Anarky (vol. 2) #8 (Dec. 1999): "The Sins of the Father"The Avengers (vol. 1) #1.5 (Dec. 1999): "The Death-Trap of Doctor Doom!"Batman / Tarzan: Claws of the Cat-Woman #4 (Dec. 1999)Birds of Prey (vol. 1) #12 (Dec. 1999): "Hellbound Train"Black Panther (vol. 3) #13 (Dec. 1999): "The End"Blade (vol. 4) #1 (Dec. 1999): "Chaos, Part One: The Dead Walk"Body Doubles #3 (Dec. 1999): "Cold Snap"Captain America (vol. 3) #24 (Dec. 1999): "The Difference!"Catwoman (vol. 2) #75 (Dec. 1999): "No Man's Land: The Rules"Daredevil (vol. 2) #9 (Dec. 1999): "Parts of a Hole Part 1: Murdock's Law"Fantastic Five (vol. 1) #3 (Dec. 1999): "Side By Side with Spider-Girl"Green Lantern (vol. 3) #119 (Dec. 1999): "Spectre of the Past"JLA #36 (Dec. 1999): "World War Three, Part One"
Madman ComicsMartian Manhunter (vol. 2) #13 (Dec. 1999): "Rings of Saturn, Episode One"The Masked Prosecutor (1999)The New Warriors (vol. 2) #3 (Dec. 1999): "Loyalties"Peter Parker: Spider-Man (vol. 2) #12 (Dec. 1999): "Another Return of the Sinister Six"Razorjack #1 (Dec. 1999): "Citadel"Secret Origins of Super-Villains 80-Page GiantSpider-Girl (vol. 1) #15 (Dec. 1999): "Swingin' N' Slammin' With Speedball!"Spider-Man Unlimited (vol. 2) #1 (Dec. 1999): "Worlds Apart"Spider-Woman (vol. 3) #6 (Dec. 1999): "I Dwelt In Darkness Dreaming"Superman (vol. 2) #151 (Dec. 1999): "We're Back!"Thor (vol. 2) #18 (Dec. 1999): "The Deadly Living Talismans!"Thunderbolts (vol. 1) #33 (Dec. 1999): "Ogres in the Shadows"The Uncanny X-Men (vol. 1) #375 (Dec. 1999): "I Am Not Now, Nor Have I Ever Been..."Warlock (vol. 5) #3 (Dec. 1999)Whiteout: Melt #3 (Dec. 1999)Wild ThingWolverineWonder Woman (vol. 2) #151 (Dec. 1999): "The Pandora Virus: Part 1"X-51 #5 (Dec. 1999): "Circuits Maximus"X-Force (vol. 1) #97 (Dec. 1999): "Cracked Foundation"X-Men (vol. 2) #95 (Dec. 1999): "Do Unto Others"X-Men UnlimitedX-Men: The Hidden Years #1 (Dec. 1999): "Once More the Savage Land"