It is a legal requirement of the forum. The copyright laws in the UK, where the forum is based, are very strict. If you don't wish to comply with the rules of the forum, that is your choice. We can simply delete this thread. If you want the thread to stay in place, give us the information.
You have had three opportunities to provide the source and author and have failed to do so. Instead, you chose to be argumentative. This thread is closed and I have removed the quote from post #1 as the source has not been cited.