《周礼·冬官考工记·轮人&輈人》
盖弓长六尺，叫做庇轵，长五尺叫做庇轮，长四尺叫做庇轸。把弓长分成三等分，而把靠近盖斗的一等分用火烤燥而变得平直。
弓长六尺谓之庇轵，五尺谓之庇轮，四尺谓之庇轸，参分弓长而揉其一，参分其股围，去一以为蚤围。
The bow-covering is six feet long and is called 庇轵, five feet long and is called 庇轮, four feet long and is called 庇轸. Divide the bow-length into three equal parts and then fire-harden and straighten the part near the lid.