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\bibitem{Ellison_etal1996} Ellison, B. N., Maddison, B. J., Matheson, D. N., Oldfield, M. L., Marazita, S., Crowe, T. W., et al. (1996). First results for a 2.5 THz Schottky diode waveguide mixer. In \textit{Proc. 7$^{th}$ Int. Symp. Space Terahertz Technol.} (494). Charlottesville, Virginia, USA.

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