Comments on "A new vector quantization clustering algorithm
R. L. Bottemiller · IEEE Transactions on Signal Processing · 1992
W.H. Equitz (IEEE Trans. Acoust., Speech, and Signal Process. vol.37, no.10, p.1568-75, Oct. 1989) presented a procedure called pairwise nearest neighbor (PNN) as a new alternative to the familiar Linde-Buzo-Gray algorithm for vector quantization. The commenter maintains that inspection of the statistical literature shows the PNN algorithm to be identical to J. Ward's hierarchical clustering method published in 1963.>