An Osaka-based civic group has launched a campaign to raise financial assistance for the children of North Korean refugees who have fled to China.According to Rescue the North Korean People/Urgent Action Network (RENK), an estimated 20,000 North Koreans have entered China over the past two years to escape hunger and the lack of political freedom in the Stalinist regime. Because those refugees are illegally staying in China, their children -- who the group estimates account for some 20 percent of all the refugees -- are not even able to go to school, said the group, which provides food aid to people in North Korea.The group is looking for donors to help cover the cost of the children's housing and schooling in China. In exchange for a minimum monthly donation of 5,000 yen, the donors will receive letters and photos from the North Korean children, RENK said.The group, established in 1993, said its purpose is to promote the democratization of North Korea. For more information, call Lee Young Hwa of RENK at (0726) 61-8431.