The Duluth Showcase Company, which later became the Duluth Refrigerator Company and then the Coolerator Company, was established in 1908. The Universal Atlas Cement Company, which made cement from the slag byproduct of the steel plant, began operations in 1917. Because of its numerous jobs in mining and industry, the city was a destination for large waves of immigrants from Europe during the early 20th century. It became the center of one of the largest Finnish communities in the world outside Finland. For decades, a Finnish-language daily newspaper, "Päivälehti," was published in the city; it was named after the former Grand Duchy of Finland's pro-independence leftist paper. The Finnish community of Industrial Workers of the World (IWW) members published a widely read labor newspaper "Industrialisti." From 1907 to 1941, the Finnish Socialist Federation and then the IWW operated Work People's College, an educational institution that taught classes from a working-class, socialist perspective. Immigrants from Sweden, Norway, Denmark, Germany, Austria, Czechoslovakia, Ireland, England, Italy, Poland, Hungary, Bulgaria, Croatia, Serbia, Ukraine, Romania, and Russia also settled in Duluth. Today, people of Scandinavian descent constitute a strong plurality of Duluth's population, accounting for more than one third of the residents identifying European ancestry. In September 1918, at the beginning of U.S. involvement in the Great War, a group calling itself the Knights of Liberty dragged Finnish immigrant Olli Kinkkonen from his boarding house, tarred and feathered him, and lynched him. Kinkkonen did not want to fight in World War I and had planned to return to Finland. His body was found two weeks later hanging in a tree in Duluth's Lester Park. Another lynching in Duluth occurred on June 15, 1920, when three innocent black male circus workers: Elias Clayton, Elmer Jackson, and Isaac McGhie, were attacked by a white mob and hanged after allegedly raping a teenage white girl. The Duluth lynchings took place on First Street and Second Avenue East. In the late 20th century, journalist Michael Fedo wrote "The Lynchings in Duluth" (1970), which began to raise awareness of the event. Community members from many different groups began to come together for reflection and education. The men's unmarked graves were located and in 1991, gravestones were erected with funding from a local church. Vigils were held at the intersection where the men were lynched.