Precise computation using range arithmetic, via C++. - Oliver Aberth; Mark J. Schaefer (ACM Trans. Math. Softw., 1992)

Precise Matrix Eigenvalues Using Range Arithmetic. - Oliver Aberth; Mark J. Schaefer (SIAM J. Matrix Anal. Appl., 1993)

A parallel complex zero finder. - Mark J. Schaefer; Tilmann Bubeck (Reliab. Comput., 1995)