Prison riots occur periodically in the former Soviet republics of Central Asia.

These commercial panics occur periodically, after the fashion of comets and earthquakes and other disagreeable things.

Mass strandings of whales occur periodically in Australia and New Zealand for reasons that are not entirely understood.

Outbreaks like the one found affecting the migrating snow geese in Idaho occur periodically in the United States and elsewhere, Losinski said.

One of those visitations of fate which occur periodically in the trenches interrupted the General's words, and ended the situation in more ways than one.

Hence there occurs periodically the scene we were about to witness.

Inter-allied research conferences occurred periodically in Paris, where decisions for co-operation were taken after full discussion of allied work.

In pre-industrial times, that occurred periodically in natural pulses of carbon that also pushed up global temperatures, the scientists wrote.

The results of demographic modeling reinforce the existence of a stably maintained population of YFV with spillover events into human populations occurring periodically.

They could not tell me whether it visited all of the islands, but I was certainly assured that it occurred periodically in some of them.