1. Beauchamp, K.G.: ‘Applications of Walsh and related functions’, (Academic Press London 1984)
2. Elliott, D.F., and Rao, K.R.: ‘Fast transforms, algorithms, analyses, applications’, (Academic Press London 1982)
3. Harmuth, H.F.: ‘Transmission of information by orthogonal functions’, (Springer-Verlag New York 1972)
4. Kulesza, W.: ‘Systems for spectral analysis of digital data’, (WKL Warsaw 1984),in Polish
5. Stojic, M.R., Stankovic, M.S., and Stankovic, R.S.: ‘Discrete transforms and their application’, (Nauka Beograd 1993),in Serbian