Bold links are technology that is currently used (either reimplemented or as a library) in the Folk core (including unmerged folk2). Italic links have been built into plugins or otherwise seriously tested by us.

• Flexible layouts for fiducial tags (AprilTag 3), Maximilian Krogius, Acshi Haggenmiller, and Edwin Olson (2019)
• ChromaTags: an accurate, robust, and fast visual fiducial system, Austin G. Walters (2015)

• DynaTags: low-cost fiducial marker mechanisms, Cassandra Scheirer and Chris Harrison (2022)
• Tangible interfaces with printed paper markers, Clement Zheng et al (2020)

• The computer for the 21st century, Mark Weiser (1991)

• Tactile manipulation on a digital desk, Pierre Wellner, Xerox EuroPARC (1991)
• Projector-based location discovery and tracking, Johnny Chung Lee (2008)
• Procession, Violet Whitney and William Martin, Spatial Pixel
• Lightform

• The Hoshen-Kopelman algorithm, Tobin Fricke (2004)

• A user-friendly method to geometrically calibrate projector-camera systems, Samuel Audet and Masatoshi Okutomi (2009)
• A flexible new technique for camera calibration, Zhengyou Zhang (1998)

• Natural language Datalog, Alex Warth (2013)
• Lock-freedom without garbage collection, Aaron Turon (2015)
• Generational indices guide
• work-stealing

• SLURP: an eyedropper for manipulating abstract, digital material, Jamie Zigelbaum et al (2008)

• RFTouchPads: batteryless and wireless modular touch sensor pads based on RFID, Meng-Ju Hsieh et al (2019)
• 3D backscatter localization for fine-grained robotics, Zhihong Luo et al (2019)
• RFID localization for interactive systems (BackTrack), Ian Clester (2020)

• DodecaPen: accurate 6DoF tracking of a passive stylus, Po-Chen Wu et al (2017)
• D-POINT: digital pen with optical-inertial tracking,