1. On the design of filters by synthesis;Saal;IRE Trans.,1958
2. Der Entwurf von Filtern mit Hilfe des Kataloges normierter Tiefpässe
3. Design of hairpin-line and hybrid haripin-parallel-coupled-line filters;Cristal;IEEE MTT-S Dig,1971
4. Microstrip tapped-line filter design;Wong;IEEE Trans.,1979