1. Sylvester, J.J.: On a funicular solution of Buffons ?Problem of the needle? in its most general form. Acta Math.14, 185?205 (1891)
2. Blaschke, W.: Vorlesungen über Integralgeometrie. Leipzig: Teubner 1936, 1937
3. Ambartzumian, R.V.: Intersections of complex curves and random stright lines. Dokl. Akad. Nauk SSSR, IV, 3,187 (1969). (English translation: Soviet Math. Dokl. 4,10 (1969)
4. Ambartzumian, R. V.: The method of invariant embedding in the theory of random lines (in russian). Izv. Akad. Nauk Armjan. SSR Dokl. Ser. Mat.5, 3, 263 (1970)
5. Ambartzumian, R.V.: Probability distributions in the geometry of clusters. Studia Sci. Math. Hungar.6, 235?241 (1971)