According to the U.S. Copyright Office:

                "There is no such thing as an “international copyright” that will automatically protect an
                 author’s writings throughout the world. Protection against unauthorized use in a particular
                 country depends on the national laws of that country."

Copyright questions that pertain to works created in other countries are notoriously difficult to research. This is largely due to the fact that each country has different laws; and, in some cases, different languages.

In an effort to provide some clarity, many countries have joined the Berne Convention for the Protection of Literary and Artistic Works. The Berne Convention was first adopted in 1886 as an agreement to honor the rights of all authors who are citizens of countries that  have joined the convention.

For a summary of the rights provided by the Berne Convention, please see the UK Copyright Service Fact Sheet.

First Step

If you plan to reproduce a significant portion of an author's work, your first step in any country is to locate the rights holder of the work in question and ask for permission. For additional information on this process, please see the Columbia University Copyright Advisory Office page.

Before embarking on an international copyright permissions project, please consider these alternatives:

Fair Use

You may be able to use a portion of the work in question by claiming fair use. However, be aware that each country's definition of what constitutes fair use may differ from U.S. law. For more information see the UK Copyright Service Fact Sheet on fair use.

Locate Alternatives

Can you locate a similar U.S. source with an identifiable copyright holder? If so then contact that rights holder and seek out the appropriate permissions. Or, you might also be able to locate an equivalent source that is in the public domain. 

Rethink Your Intended Use

Rather than use the entire work can you cite a small portion of the work or even paraphrase relevant points? Relying on quotations, paraphrasing, and proper citation methods can often help you avoid the copyright permissions process altogether.