User talk:Up900419

November 2020
Hello, I'm Materialscientist. I noticed that you made a change to an article, Sociotechnical system, but you didn't provide a source. I’ve removed it for now, but if you’d like to include a citation to a reliable source and re-add it, please do so! If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Thanks. Materialscientist (talk) 16:46, 4 November 2020 (UTC)