While I recommend checking your local library for the book titles listed in this study, you can also contact Homeschoolers of Maine to see if they have any of them
in The Heart of HOME Bookstore. The bookstore is open at their annual Convention, and the Used Curriculum Sale in the spring. I have also provided links for ordering these books at either
Amazon.com or Christian Book Distributors. Of course there is always ebay, your local homeschool book sales, and your friends' bookshelves!