"This is data under primary energy sources of all the countries.

VOA: standard.2010.08.03

We have other--lots of data sources-- that Yale subscribes to and there are lots of free data sources, but Wall Street Journal Online is not free.

我们也有很多其他数据来源,耶鲁订阅了不少,并且还有免费信息,但《华尔街日报在线》是收费的

耶鲁公开课 - 金融市场课程节选