1. Aiello, L. C., & Wheeler, P. (1995). The expensive-tissue hypothesis: the brain and the digestive system in human and primate evolution. Current Anthropology, 36, 199–221.
2. Bock, W. J., & von Wahlert, G. (1965). Adaptation and the form-function complex. Evolution, 19, 360–299.
3. Breidbach, O., & Wegerhoff, R. (1993). Neuroanatomy of the central nervous system of the harvestman, Rilaena triangularis (Herbst 1799)(Arachnida; Opiliones): principal organization, Gaba-like and serotonin-immunohistochemistry. Zoologischer Anzeiger, 230(1-2), 55–81.
4. Bromhall, C. (1987). Spider tracheal systems. Tissue & Cell, 19(6), 793–807.
5. Coddington, J. A., Giribet, G., Harvey, M. S., Prendini, L. & Walter, D. E. (2004). Arachnida. In Assembling the tree of life, 296-318.