Black South Africans have gone back to work following Monday's strike, but resistence to the government's state of emergency regulations continues. Several hundred black workers at Johannesburg supermarkets staged strikes yesterday to protest the detention of union leaders. The government reported three more black deaths linked to the unrest, and extended a ban on reporting police activity to include actions in six of South Africa's ``homelands.'' Four West Germans and a Dutch cameraman have been expelled from the country under the emergency decree. Pretoria also confirmed that new restrictions were placed on black activist Winnie Mandela.