Last names in English composed of more than one element are usually shortened to the final element, so a name like Harriet Beecher Stowe would be shortened to Stowe. Practices vary, however, so it’s best to consult a dictionary.

For names not listed in the dictionary, consult a reputable source, like the Library of Congress catalog, or cross-check against news articles or other works that refer to the person. For example, the last name of the writer Jonathan Safran Foer is shortened in the Library of Congress catalog and in news articles to Foer, but the last name of the English composer Andrew Lloyd Weber is shortened in the Library of Congress catalog and in news articles to Lloyd Weber. If you are unable to find the information in a reliable source, shorten the last name to the final element.

If you are working directly with the person, ask for the preferred form of reference.