瑜伽論記 1.428

1.428

剩明賢劫量者，補闕解：有人云，非水火劫，乃約千佛前後出時，經於百千火水等劫遠亘長時，總名賢劫。

As an extra clarification of the duration of the Bhadrakalpa, the Supplement explains: Some say it is not a water or fire kalpa, but is reckoned in terms of the times when the thousand Buddhas successively appear, spanning across hundreds of thousands of fire and water kalpas as a far-reaching, vast duration, collectively termed the Bhadrakalpa.