1. A convenient transformer for matching coaxial lines;Bramham;Electron Eng,1961
2. Double-layer matching structures;Kott;IRE Trans Microwave Theory Tech,1962
3. Short-step Chebyshev impedance transformers;Matthaei;IEEE Trans Microwave Theory Tech,1966
4. Double section matching transformers;French;IEEE Trans Microwave Theory Tech,1969
5. Matching of immittances of one- and two-step transformers of minimum length [in Russian];Freidin;Radiotekhnika,1983