User talk:199.38.31.113

Recent edit to Gravitational energy
Hello, and welcome to Wikipedia. I noticed that you made a change to an article, Gravitational energy, but you didn't provide a reliable source. It's been removed for now, but if you'd like to include a citation and re-add it, please do so! If you need guidance on referencing, please see the referencing for beginners tutorial, or if you think I made a mistake, you can leave me a message on my talk page. Thank you! ◢    Ganbaruby!    (talk to me) 22:39, 5 November 2019 (UTC)