Рибін, О., and А. Ткачук. “The Analisis of Linear Systems in Basis of Walsh-Hadamard Transformation”. Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, no. 33, Sept. 2006, pp. 14-23, doi:10.20535/RADAP.2006.33.14-23.