Building Instructions for a cable that connects LEGO Power Functions (PF) with Mindstorms NXT/EV3 - Christoph Bartneck, Ph.D.
LEGO Technique Parts Hole Rods Connectors Pins Gears etc of Choice Gray NEW | eBay
LEGO Powered Up Connector | Marek's microsite
Power Functions motors presentation
Amazon.com: 844Pcs Pins-Gears-Axles Set Compatible with Lego-Technic-Parts, Latest differentials Chain Link Connector Joints Tank Track Car-Wheels-Tires Shock-Absorber Steering Shaft : Toys & Games
LEGO Powered Up Connector | Marek's microsite
How to Hack a LEGO Power Functions Cable for Direct 9V Power - GeekDad