《旧唐书·列传·卷一百二十四》
西戎人行动迟钝，地广人稀，每次想乘秋季犯我边境，都须移兵粮多地区数年。
犬戎迟钝，土旷人稀，每欲乘秋犯边，皆须数岁就食。
The barbarians in the west are slow and there are few people over a large territory. Each time they have considered attacking our border in the autumn, they have had to first transport troops and supplies [over] many regions [over the course of] several years.