M. Losada, R. Medina, C. Vidal, and I. Losada. Coastal Engineering 1992, Proceedings of the Twenty-Third International Conference., page 2251--2264. Venice, Italy, (4-9 October 1992)
M. Ottaviani. Research Report, A33. Department of Statistics, Probability and Applied Statistics, University of Rome "La Sapienza", Rome, Italy, (1990)
A. Rizzi, and M. Vichi. Some relations between matrices and structures of multidimensional data analysis ., Giardini Editori e Stampatori, Pisa, (1995b)