Sergio Spagnolo, “Local and Semi-Global Solvability for Systems of Non-Principal Type”, Communications in Partial Differential Equations, 25:5-6 (2000), 1115
Sergio Spagnolo, “On the absolute continuity of the roots of some algebraic equations”, Ann. Univ. Ferrara, 45:1 (1999), 327
Stefano Campi, Andrea Colesanti, Paolo Gronchi, “Blaschke-decomposable convex bodies”, Isr. J. Math., 105:1 (1998), 185
Seiiehiro WAKABAYASHI, “Singularities of solutions of the Cauchy problem for hyperbolic systems in Gevrey classes”, Jpn. j. math, 11:1 (1985), 157
Seiichiro Wakabayashi, “Singularities of solutions of the caught problem for symmetric hyperbolic systems”, Communications in Partial Differential Equations, 9:12 (1984), 1147
Seiichro Wakabayashi, “Singularities of solutions of the cauchy problems for operators with hearly constant coefficient hyperbolic principal part”, Communications in Partial Differential Equations, 8:4 (1983), 347
В. Г. Болтянский, “Комбинаторная геометрия”, Итоги науки и техн. Сер. Алгебра, топол., геом., 19 (1981), 209–274; V. G. Boltyanskii, “Combinatorial geometry”, J. Soviet Math., 23:6 (1983), 2753–2789