. . "Gassen." . . "Ionisatie." . . "Botsingen." . . . . . . . . . . "The theory of ionization of gases by collision" . . . "The theory of ionization of gases by collision"@en . . . . . . "The Theory of Ionization of Gases by Collision"@en . . . . . . . . . . . "Theory of ionization of gases by collision"@en . . . . "Geleidingsvermogen." . .