http://www.tubebooks.org/tubedata/RC30.pdf
http://www.nmr.mgh.harvard.edu/~reese/RC10/
http://w5jgv.com/downloads/RC-14.PDF
http://www.dhtrob.com/overige/pdf/RCA_1962_ReceivingTubeManual_RC13.pdf
http://www.smcelectronics.com/DOWNLOADS/1956%20RCA%20XMIT%20TUBE%20MANUAL.PDF
http://www.pmillett.com/tubebooks/Books/intro_army_theory.pdf
http://www.tubebooks.org/Books/re.pdf