K-eXplorer: Cellular phone ubiquitous real-world interface with distributed K-stations. - Yasushi Ikei; Hiroyuki Eguchi; Ken Ishigaki (ICAT, 2007)

Wearable Memorization Aid for Human Memory Augmentation. - Yasushi Ikei; Ken Ishigaki (ISUC, 2008)

Spatial memorization aid system: registration of mental memory space. - Ken Ishigaki; Yasushi Ikei (IUCS, 2009)

Image Mnemonics for Cognitive Mapping of the Museum Exhibits. - Yasushi Ikei; Ken Ishigaki; Hirofumi Ota; Keisuke Yoshida (HCI (5), 2016)