Jenny McLeod's treatise on Tone Clock Theory comes from both her practice and study, having first come across the formal idea in the 1980s when she met the Dutch composer Peter Schat. She has written a number of works, particularly for piano, based on this harmonic theory which utilises the twelve triads that are possible within the twelve note chromatic system.
Tone Clock Theory Expanded: Chromatic Maps I & II is available from this site as a "free download":http://sounz.org.nz/catalog/BO1095DS.pdf. (15.7MB pdf)
Informally published in 1994 as "Chromatic Maps I & II" by the Victoria University of Wellington School of Music, Wellington, New Zealand - a version without the Preface and appendices.