Lappone: Tunisian Crochet (in Swedish: "krokning")
DOUBLE ENDED CROCHET HOOK SET – INCLUDES 8 HOOKS — GuChet.com - Yarns, Patterns and Accessories
Double-ended hook worked flat - Rachel Henri crochet design
Double-ended Tunisian crochet - Rachel Henri crochet design
Learn to Crochet with Double End Hook and Red Heart - Part 2 - YouTube
I know a lot of people prefer double ended Tunisian crochet to work in the round, but this is my favorite way to make hats using Tunisian crochet. Basically, magic ring knitting,
Double-ended crochet - work in a spiral - Rachel Henri crochet design
Ravelry: Double-Sided Crochet Whatever pattern by Darlisa Riggs
Cro-Hook (Double-Ended Tunisian Crochet) - CrochetKim™