BRUSSELS, April 19 (Reuters) - Forty-two German associations and trade unions representing more than 140,000 authors and performers on Wednesday urged the European Union to beef up draft artificial intelligence rules as they singled out the threat to their copyright from ChatGPT. "The unauthorised usage of protected training material, its non-transparent processing, and the foreseeable substitution of the sources by the output of generative AI raise fundamental questions of accountability, liability and remuneration, which need to be addressed before irreversible harm occurs," the letter seen by Reuters said. See here for a complete list of exchanges and delays