I didn't write the IOUs. Who did you borrow the money from? Is what others wrote useful? If you don't write an IOU, it's invalid to write the money you borrowed from anyone, because only if you type the IOU yourself can you admit that you borrowed money from others. This iou is valid. If someone writes a name that you borrowed, it is not legally recognized because you didn't sign the note yourself. If someone writes your name and you sign it yourself, this note will be recognized by law. This iou is valid. Failure to sign is an invalid law. Whether it is valid or invalid according to the facts. It's not who said who borrowed the money. No conclusive evidence is invalid and there is no need to repay it.