The country's vital cashew nut crop provides a modest living for most of Guinea-Bissau's farmers and is the main source of foreign exchange.

BBC: Guinea-Bissau profile

Under a trade deal with the European Union called GSP-plus, Sri Lanka's garment exports (its second-largest source of foreign exchange) enjoy duty-free access to the EU. But GSP-plus hinges partly on human rights.

ECONOMIST: Sri Lanka

And remittances, a big source of foreign-exchange revenue in the region, could fall steeply in a prolonged slowdown.

ECONOMIST: Central Asia and the financial crisis: After the boom | The

If the source of the foreign exchange is inward investors, not exporters, a country can impose capital controls to deter them.

ECONOMIST: How to live with an overvalued currency