This kind of book published by a regular publishing house and widely used in the whole country cannot be found in electronic version unless it is published by this publishing house. It is illegal for someone to scan or copy it. You can go to a nearby university to find used books. It is precisely because the old books of this book are easy to find and not expensive, so no one scans and copies them, which is the fundamental reason why there is no electronic version. This is illegal and useless. Who will do it?