Bohner, M., Hui, S., Brain state in a convex body, IEEE Trans. Neural Networks 6 (1995), no. 5, 1053-1060
The Erdös number of the second kind is defined inductively as follows:
The Erdös number of the second kind of Paul Erdös is 0.
The Erdös number of the second kind of X is less then or equal to n+1 if there is Y whose Erdös number of the second kind is less then or equal to n and X and Y have published a common paper as the only two authors.
My Erdös number of the second kind is less than or equal to 4:
Erdös, P., Sarközi, A., On isolated, respectively consecutive large values of arithmetic functions, Acta Arith. 66 (1994), no. 3, 269-295
Elbert, A., Sarközi, A., Über rationale Polynome (German), Ann. Univ. Sci. Budapest. Bötvös Sect. Math. 5 (1962), 155-171
Dosly, O., Elbert, A., Conjugacy of half-linear second-order differential equations, Proc. Roy. Soc. Edinburgh Sect. A 130 (2000), no. 3, 517-525
Bohner, M., Dosly, O., Positivity of block tridiagonal matrices, SIAM J. Matrix Anal. Appl. 20 (1998), no. 1, 182-195