PhantomFolds: Exploring Unobtrusive Spatial Tactile Feedback Produced by Two Fingernail Mounted LRAs for In-Air and On-Surface Mixed Reality Applications. - Messerschmidt, Moritz Alexander; Matthies, Denys J. C.; Sasikumar, Prasanth; Nanayakkara, Suranga (International Journal of Human-Computer Interaction, 2026)