The following sources are referenced in Essential Graphing.
Aitchison, J. (1986). The Statistical Analysis of Compositional Data. London: Chapman & Hall.
Box, G. E. P., Hunter, W. G., and Hunter, J. S. (1978). Statistics for Experimenters. New York: John Wiley & Sons.
Cornell, J. A. (1990). Experiments with Mixtures. 2nd ed. New York: John Wiley & Sons.
Few, Stephen (2008). “Dual-Scaled Axes in Graphs.” Visual Business Intelligence Newsletter. http://www.perceptualedge.com/articles/visual_business_intelligence/dual-scaled_axes.pdf.
Hyndman, R. J. (1996). “Computing and Graphing High Density Regions.”The American Statistician 50: 120 - 126.
Hyndman, R. J., Koehler, A. B., Ord, J. K., and Snyder, R. D. (2008). Forecasting with Exponential Smoothing: The State Space Approach. Berlin: Springer-Verlag.
Inselberg, A. (1985). “The Plane with Parallel Coordinates.” Visual Computing 1: 69–91.
Mardia, K. V., Kent, J. T., and Bibby J. M. (1979). Multivariate Analysis. New York: Academic Press.
Rousseeuw, P. J., Ruts, I., and Tukey, J. W. (1999). “The Bagplot: A Bivariate Boxplot.” The American Statistician 53: 382 - 387.
Wegman, E. J. (1990). “Hyperdimensional Data Analysis using Parallel Coordinates.” Journal of the American Statistical Association 85: 664–675.