Fishman, N.H. , Bogren, H.G. and Carlsson E.S.: Angiographic estimation of the size of the aortic valve annulus, Arch. Surg.101: 717, 1970 .
2.
Bergström, K. , Erikson, U., and Gustafsson , B.: Roentgenological determination of the heart volume, Acta Soc. Med. Upsal.74: 81, 1969.
3.
Friedenberg, M.J., Carlsson, E., Hartmann, A.F. and Behrer, M.R.: Evaluation of the degree of aortic valve stenosis by direct roentgenologic measurement of the ostium, Amer. J. Roentgenol.91: 1347, 1964.
4.
Stein, P.D.: Roentgenographic method for measurement of the cross-sectional area of the aortic valve, Amer. Heart Journal81: 622, 1971.
5.
Hemmingsson, A. and Lodin, H.: Zur Funktion das ITV-System des Akademischen Krankenhauses in Uppsala. To be published in Röntgenblätter .