During the final scenes of the episode the girls can be heard in the playground making a wheel to the song "En Cádiz hay una niña." This is a classic Spanish children's song which was also the inspiration for the series' opening theme "Hay en Madrid una niña."
This is the only episode to have been named after one of Elena Fortún's "Celia" books: "Celia en el colegio" (1932).