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\bibitem{Grimes_etal2003} Grimes P, Kittara P, Yassin G, Withington S, Jacobs K. Investigation of the performance of a 700 GHz nline mixer. In: Proc. 14$^{th}$ Int. Symp. Space Terahertz Technol. Tucson, USA; 2003. 247.

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