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\bibitem{Bals_etal2001} {\textquotedblleft}\textit{Why are sputter deposited Nd$_{1+x}$Ba$_{2-x}$Cu$_{3}$O$_{7-\delta}$ thin films flatter than NdBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films?}{\textquotedblright}.Bals S, Van Tendeloo G, Salluzzo M, Maggio-Aprile I, Applied physics letters \textbf{79}, 3660 (2001).   http://doi.org/10.1063/1.1421622

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