How to Evolve Pichu and Pikachu in Pokemon Sun and Moon - Pokemon Sun & Pokemon Moon Wiki Guide - IGN
Pychu: Pikachu's Fire-Type Evolution by KelseyEdward on DeviantArt
How to Evolve Pikachu: 4 Steps (with Pictures) - wikiHow
Red's Pikachu (game) - Bulbapedia, the community-driven Pokémon encyclopedia
Why on earth can't Pikachu Evolve?! This is such a silly thing imo (and please for the love of god, don't say "It could be Ash's Pikachu") : r/PokemonUnite