Altering Cave - Pokemon Fire Red and Leaf Green Guide - IGN

Found north of Sixth Island, this cave only have Zubats. However, if you have an E-reader connected to a gameboy advance using Japanese E-reader cards

Three Island - Pokemon Fire Red and Leaf Green Guide - IGN

One Island - Pokemon Fire Red and Leaf Green Guide - IGN

PK3/WC3: Unreleased Altering Cave Pokémon - Unreleased/Beta PKM

Pokémon FireRed/LeafGreen - Guides - Speedrun

Route 2 - Pokemon Fire Red and Leaf Green Guide - IGN

How Pokémon FireRed and LeafGreen Set the Bar For All Video Game

Seafoam Islands - Pokemon Fire Red and Leaf Green Guide - IGN

Pokemon LeafGreen Version [Walkthroughs] - IGN

Pokemon Leaf Green Version - Ep.47 - Altering Cave

Pokemon FireRed/LeafGreen Walkthrough - PokeDream