YELLOWSTONE NATIONAL PARK, Wyo. (AP) _ After an absence of decades, vintage yellow tour buses return this summer to Yellowstone National Park. The buses haven't been seen in Yellowstone since the 1960s. Now eight buses, built in the 1930s and refurbished over the past year, will provide tours for Yellowstone visitors, beginning June 4th. Events in Livingston and in Cody, Wyoming, on June 1st will commemorate the buses' return. The buses will be in Gardiner the next day for a ceremony and parade through the Yellowstone Arch. By June 4th, they'll be divided between Canyon, Lake, Old Faithful and Mammoth Hot Springs for daily tours through the summer. One of the buses will be used for customized tours.