1. The literature list contains papers mentioned in the text as well as other papers of interest.
2. Andersen, NT, Hobolth, A, Gregersen, H, Væth, M. 2000. Implicitly defined non-linear models of elastic properties of organs. Research Report 2000–4, August. Department of Biostatistics, University of Aarhus, Denmark.
3. Assentoft, JE, Gregersen, H, O’Brien, WD. 2000. Determination of biomechanical properties in the guinea pig esophagus by means of high-frequency ultrasound and impedance planimetry. Dig Dis Sci, 45,1260–66.
4. Assentoft, JE, Gregersen, H, O’Brien Jr., WD. 2001. Propagation speed of sound assessment in the layers of the guinea pig esophagus by means of acoustic microscopy. Ultrasonics, 39, 263–8.
5. Assentoft, JE, Jørgensen, CS, Gregersen, H, Christensen, LL, Djurhuus, JC, O’Brien, WD. 1996. Scanning laser acoustic microscopy as a method for characterizing the acoustic properties of the individual layers of biological tissue. IEEE Eng Med Biol Mag, 15, 42–5.