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2. Untersuchungen über einen in Mundhöhle u. s. w.;Ørskov;Acta Path. et Microb. Scandinav.,1930
3. Method for the demonstration of bacterial flagellum activity. Direct indian ink agar microscopy;Ørskov;Acta path. et Microb. Scandinav.,1947
4. Function and Arrangement of Bacteria Flagella;Boltjes;J. Path. & Bact.,1948
5. Comment of Pijper's film of moving bacteria;Boltjes;Antonie van Leeuwenhoek,1948