"Introversion." . . "Work measurement." . . . . "The relationship of introversion-extroversion to physical persistence"@en . . . . . . . . . . . . . . . . "The relationship of introversion-extraversion to physical persistence"@en . "The relationship of introversion-extraversion to physical persistence" . . . . . "Extraversion." . . "Physical education and training." . . . . "Persistence." . .