1. For the early history of development we have relied on: Berggren, U. (1985) “CT scanning and ultrasonography: A comparison of two lines of development and dissemination,” Research Policy, 14, pp. 213–223.
2. Hamilton, B. (1982) Medical Diagnostic Imaging, New York: F & S Press.
3. Klein Biomedical Consultants (1980) The Medical Diagnostic Ultrasound Market, New York: Klein Biomedical.
4. Friar, J.H. (1993) “Targeting initial customers and applications for emerging technologies,” paper presented at the Academy of Management, August 11, Atlanta, Georgia.
5. See for example: American Journal of Diseases in Children, (1981) 135, p.961.