Kinematic and Tube Formulas for Piecewise Linear Spaces J. CheegerW. MullerR. Schrader Indiana University Mathematics Journal 1986 text pdf 10.1512/iumj.1986.35.35039 10.1512/iumj.1986.35.35039 en Indiana Univ. Math. J. 35 (1986) 737 - 754 state-of-the-art mathematics http://iumj.org/access/