BERN, Switzerland (AP) — The Swiss government says a referendum will take place on a nationalist-led proposal to introduce annual quotas for immigrants.The government said in a statement Wednesday that a campaign group called Stop Mass Immigration has gathered the necessary 100,000 signatures to force a referendum.The nationalist Swiss People's Party has promoted the campaign with posters of black boots marching onto the Swiss flag.The plan foresees caps for all types of foreigners living and working in Switzerland.