1. Serup J. Ten years experience with high frequency ultrasound examination of the skin. In: Hoffman K, editor. Ultrasound in Dermatology. 1st ed. Germany: Springer-Verlag; 1992. p. 41-54.
2. Hoffmann K, El Gammal S, Winkler K, Jung J, Pistorius K, Altmeyer P. Skin tumours in high frequency ultrasound. In: Altmeyer P, El Gammal S, Hoffmann K, editors. Ultrasound in Dermatology. 1st ed. Heidelberg, Germany: Springer-Verlag; 1992. p. 181-201.