"Canada" . . . . . . . . . "Aerological data for northern Canada upper wind frequencies, average upper-air temperature, pressure and humidity data, surface climatic data for selected stations [and] normal isobaric charts"@en . . . . . "Aerological data for northern Canada; upper wind frequencies, average upper-air temperature, pressure and humidity data, surface climatic data for selected stations [and] normal isobaric charts" . . . "Aerological data for northern Canada: upper wind frequencies, average upper-air temperature, pressure and humidity data, surface climatic data for selected stations, normal isobaric charts" . . . . . . . . . .