. _:b19608 . _:b19606 . _:b19607 . _:b19606 _:b19607 . . . _:b19606 . _:b19608 . "Al" . _:b19607 . _:b19608 . "Alfv\u00E9n number"@en . _:b19607 . _:b19608 . _:b19606 .