Marsh, F. L. (1976). Variation and fixity in nature: The meaning of diversity and discontinuity in the world of living things, and their bearing on creation and evolution. Pacific Press.

Marsh, Frank L. Variation and Fixity in Nature: The Meaning of Diversity and Discontinuity in the World of Living Things, and Their Bearing on Creation and Evolution. Mountain View, CA: Pacific Press, 1976.

Marsh, Frank L. Variation and Fixity in Nature: The Meaning of Diversity and Discontinuity in the World of Living Things, and Their Bearing on Creation and Evolution. Pacific Press, 1976.