Elinor Ostrom has become the first woman to win the Nobel prize for economics since it began in 1968.

Elinor Ostrom成为自1968年设立以来首位获得诺贝尔经济学奖的女士。

Ms Ostrom won the prize with fellow American Oliver Williamson for their separate work in economic governance.

The Nobel Memorial Prize in Economic Sciences is the last of the six Nobel prizes announced this year. Since 1980, it has gone to Americans 24 times.

Last Friday, US President Barack Obama was awarded the Nobel Peace Prize - though this aroused some controversy.

BBC economics editor Stephanie Flanders said the judges had rewarded work in areas of economics whose practitioners（开业者，从业者）' "hands were clean" of involvement in the global financial crisis.

'Great surprise'

The economics prize was not among the original Nobel awards, but was created in 1968 by the Swedish central bank in Alfred Nobel's memory.

The Royal Swedish Academy of Sciences cited Professor Ostrom, who teaches at Indiana University, "for her analysis of economic governance," saying her work had demonstrated how common property could be successfully managed by groups using it.

She told Swedish television that she was "in shock" at being the first woman to clinch（敲弯，扭住） the award, adding winning had been a "great surprise".

Meanwhile, Professor Williamson, the academy said, developed a theory where business firms served as structures for conflict resolution.

The University of California, Berkeley academic has argued that hierarchical（分层的，体系的） organisations such as companies represent alternative governance structures, which differ in their approaches to resolving conflicts of interest.

"Over the last three decades, these seminal contributions have advanced economic governance research from the fringe（边缘，端） to the forefront of scientific attention," the academy said.

The pair will share the 10-million Swedish kronor (£910,000; $1.44m) prize.

Last year, American academic Paul Krugman won the prize, in recognition of his analysis of trade patterns and where economic activity takes place.