Question: What was the country of origin of one of the major users of Butterfly style in 1980's hockey?
Sentence (from "Butterfly style"): Many factors helped make it a "de facto" standard style of play today, including the popularization of the goalie mask by Jacques Plante, Vladislav Tretiak's outstanding use of the style at the 1972 Canada–USSR Summit Series, the National Hockey League (NHL) emergence of Tony Esposito in the 1970s and Patrick Roy in the 1980s, the development of lightweight materials for pads and the influence of professional goaltending coaches such as Warren Strelow, Benoit and François Allaire.
Relevant evidence: Yes