ISBN 1-930051-22-0 Peter Singer, Ethics into Action : Henry Spira and the Animal Rights Movement -LRB- Lanham, MD : Bowman & Littlefield, 1998 -RRB-.
ISBN 0-02-916195-9 Peter Singer, Ethics into Action : Henry Spira and the Animal Rights Movement -LRB- Lanham, MD : Bowman & Littlefield, 1998 -RRB-.