| 摘要 |
A file comprises a rectangular cover having a front wing, a rear wing, and a spine between the wings. A lever arch mechanism is secured to the rear wing close to the spine to receive and retain thereon punched paper sheets. The side edges of the spine are inclined to the lower edge of the spine at a small angle. The file is extremely stable when standing on its lower edges. Another file has the cover in the form of a parallelogram with the side edges of the wings and spine parallel and inclined at a small angle to the top and bottom edges. A third file has its wings of rectangular shape with the lower edge of the spine inclined relative to the side edges of the spine.
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