Here are a couple of very useful resources free for you to download:
The UNESCO Thesaurus is widely used to standardize the terminology used to describe content in the areas of education, science, culture, social and human sciences, information and communication, and politics, law and economics. It also includes the names of countries and groupings of countries: political, economic, geographic, ethnic and religious, and linguistic groupings. Check it out!
Micro CDS/ISIS is an advanced non-numerical information storage and retrieval software developed by UNESCO since 1985 to satisfy the need of organizations to streamline their information processing activities by using modern (and relatively inexpensive) PC technologies.