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\bibitem{Tretyakov_etal2015} Tretyakov I, Maslennikov S, Semenov A, Safir O, Finkel M, Ryabchun S, et al. Impact of operating conditions on noise and gain bandwidth of NbN HEB mixers. In: Proc. 26$^{th}$ Int. Symp. Space Terahertz Technol.; 2015. 39.

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