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\bibitem{Merkel_etal2001} Merkel HF, Khosropanah P, Sigfrid Yngvesson K, Cherednichenko S, Kroug M, Adam A, et al. An active zone small signal model for hot-electron bolometric mixers. In: Proc. 12$^{th}$ Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. 55.

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