Krutch, J. W., & Landacre, P. (2009). The great chain of life (1st University of Iowa Press ed.). University of Iowa Press.

Krutch, Joseph Wood, and Paul Landacre. The Great Chain of Life. 1st University of Iowa Press ed. Iowa City: University of Iowa Press, 2009.

Krutch, Joseph Wood, and Paul Landacre. The Great Chain of Life. 1st University of Iowa Press ed. University of Iowa Press, 2009.