1. Acoustics and Psychoacoustics;Howard,2009
2. Introduction: singing at the turn of the century;Potter,2000
3. Bethel, R., Preferred Vocal Emission for Handel‘s Arias: a case study, Abstracts of NEMA International Conference, 7–10 July, York, UK, 2009. http://www.rma.ac.uk/news-and-events-html/Abstracts_for_NEMA_conference_at_York.pdf (accessed 13.02.11).
4. Bethel, R., A Research report on the early music scene in the UK, In: NEMA Survey Report, October, 2009. http://www.tvemf.org/NEMA/NEMA_survey_report.pdf (accessed 13.02.11).
5. Electroglottography/Electrolaryngography;Howard,2009