Instructions for Making Origami Polyhedra
Instructions for Making Other Origami Figures
Mathematics in Origami
Using Origami to Teach Standard Mathematics Topics
Origami as a Field of Mathematics
Applications of Mathematical Origami
History of the Sonobe Module
David Lister is an origami historian who is currently investigating the history of modular origami. He has posted a number of articles on the history and philosophy of origami. His page includes an article about the Origins of the Sonobe Module. David was kind enough to answer some of my questions about the origin of the Sonobe module by e-mail.
As far as David knows, there is no authoritative documentation stating that Mitsunobu Sonobe invented the module that now bears his name. Sonobe was a member of the Sosaku Origami Group 67 founded by Toshie Takahama. A picture of a cube created by Sonobe appears in a 1968 magazine issued by the origami group. Takahama used 3 Sonobe modules to create the figure known as "Toshie's Jewel" in the early 1960s. The Jewel and many related figures appear in several of her origami books. Because of this, some people have attributed the module to her. David thinks it is likely that Sonobe invented the module, but since Sonobe and Takahama frequently worked together, it may not be possible to determine definitively which of them originated it.