sheep keeping for pleasure and profit. 3 Burroughs Irvine, CA 92618: HobbyFarm Press, an imprint of BowTie Press, a division of BowTie Inc. 2005. ISBN 1-931993-49-1
(页面存档备份,存于互联网档案馆) Library of Congress: Jefferson exhibition (页面存档备份,存于互联网档案馆) "The Hobby of My Old Age": Jefferson's University of Virginia (页面存档备份,存于互联网档案馆) B.