听力原文： A Kosovan man was killed and three others injured in Calais when a gunman opened fire after an argument between traffickers smuggling refugees into Britain. British tourists watched as the battle broke out at the ferry terminal at the Channel port, and a stray bullet lodged in one Briton's camper van. Witnesses said that the gunman, who is thought to be a Kosovan, pulled out a pistol and fired on a group of about ten other Kosovans in the lorry part at the port. Between whom did the battle break out?