Mr. Shiner's comment encouraged me to post this.
One of my favorite people, a former AEA councillor, a brilliant dance captain and all-around brilliant performer is writing a series of how-to books for working on Broadway, to help a lot of folks. These are small books covering a broad range of topics. Several are already done, and she is about to publish her book on being a dance captain (she has been a swing and dance captain for so many shows, including the Evita tour, the recent American in Paris and way too many others to list). Worth checking out.
www.bethebestonbroadway.com Specifically, her book about being a swing is here:
https://www.amazon.com/Be-best-SWING-Broadway/dp/1497464749?ie=UTF8&keywords=be%20the%20best%20swing%20on%20broadway&qid=1405340974&ref_=sr_1_17&sr=8-17Just sharing -