RETRACTED: Retraction noticeRetraction notice to: Design and analytical modeling of folded waveguide traveling wave tube [Nucl. Instr. and Meth. A 612(1) (2009) 176–186], doi:10.1016/j.nima.2009.09.056

The Publisher regrets that this article was an accidental duplication of an article in Computers and Geotechnics. The duplicate article has therefore been withdrawn.