Here are some more sources - http://en.wikipedia.org/wiki/Singular_they#Gender-neutral_language_movement http://en.wikipedia.org/wiki/Singular_they#Gender-neut

Here are some more sources - http://en.wikipedia.org/wiki/Singular_they#Gender-neutral_language_movement http://en.wikipedia.org/wiki/Singular_they#Gender-neutral_la... and http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Singular_they.html http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Singula... Using the singular-they seems to be completely acceptable and preferable to the alternatives provided by the author.