Daniel 8:22
Now that being broken, whereas four stood up for it, four kingdoms shall stand up out of the nation, but not in his power.
Cross-reference
Daniel 8:8
Parallel
Daniel 8:8 directly describes the great horn broken and four horns rising, which Daniel 8:22 then explains.
Daniel 11:4
Parallel
In Daniel 11:4, Alexander's empire is divided into four parts after his death, exactly matching the four horns from the broken horn.
Daniel 7:6
Parallel
In Daniel 7:6, the leopard with four heads symbolizes the same four Greek successor kingdoms as the four horns here.