diff --git a/README.md b/README.md
index c09d55a..d00cb86 100644
--- a/README.md
+++ b/README.md
@@ -277,6 +277,7 @@ Sorted alphabetically by company name and product name.
 - [Siemens C1613 Plotter Manual (German)](https://archive.org/details/SiemensC1613Manual)
 - [Silver Reed Colour PenGraph EB-50 Operating Manual (1984)](https://archive.org/details/silver-reed-colour-pengraph-eb-50-operating-manual)
 - [Taxan X-Y Plotter KPL 710 Instruction Manual](https://pzwiki.wdka.nl/mediadesign/File:Taxan_kpl710_x-y_plotter.pdf)
+- [Tectronix 4662 Interactive Digital Plotter User Manual (1976)](https://archive.org/details/bitsavers_tektronix42InteractiveDigitalPlotterUserManualNov1_40423494)
 - [Tectronix HC100 Instruction Manual (1987)](https://archive.org/details/manualsonline-id-212d14c3-7d2f-4e64-906f-1a22e86d1f35/)
 - [Panasonic RK-P400C 4-Color Graphic Penwriter Manual](https://archive.org/details/panasonic-rk-p-400-c-manual)
 - [Panasonic Penwriter Manual Excerpt: RS232 Protocol Section](https://archive.org/details/panasonicpenwriterprotocol)