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\bibitem{Zhao_etal2015} {\textquotedblleft}\textit{Effects of feedstock availability on the negative ion behavior in a C$_{4}$F$_{8}$ inductively coupled plasma}{\textquotedblright}. Zhao S-X, Gao F, Wang Y-P, Wang Y-N, Bogaerts A, Journal of applied physics \textbf{118}, 033301 (2015).   http://doi.org/10.1063/1.4926867

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