Pokémon HeartGold/SoulSilver (Game) - Giant Bomb

Remakes of the original Game Boy Color games, Pokémon HeartGold and SoulSilver are given updated graphics and gameplay on the Nintendo DS.

Koffing (Pokémon) - Bulbapedia, the community-driven Pokémon encyclopedia

Pokemon Heartgold Soulsilver 2 in 1 DS Game R4 Cartridges

Pokemon HeartGold (Game Only) - Nintendo DS, Nintendo DS

Ethan (Character) - Giant Bomb

Pokémon HeartGold and SoulSilver Versions

Pokémon Heart Gold & Soul Silver - Pokéathlon

Parasect, Pokémon Wiki

Pokemon SoulSilver Version Review for DS: - GameFAQs

Pokémon HeartGold and SoulSilver - Wikipedia

Heartgold Pokemon