 Complete the following phrase:  Juckes was chosen to be part of the Canadian delegation to the meetings in 1969, which aimed to negotiate the use of professionals in IIHF competitions, before Canada ultimately withdrew from international competition in 1970. Later the same year, he and the CAHA offices relocated to Ottawa. Juckes and the CAHA cooperated with Charles Hay of Hockey Canada to persuade the Soviet national team to take part in what became the 1972 Summit Series. Juckes is also credited with the efforts that established the World Junior Championship. He used his position as an IIHF director to negotiate an upper age limit of 20 for the juniors, which had been a main point of contention with European delegates, and prevented any previous agreement for sanctioned events. The first official tournament was the 