Judith J. McDonald; Dale D. Olesky; Hans
Schneider; Michael J. Tsatsomeros; Pauline van den
Driessche
Z-Pencils,
Electron. J. Linear Algebra 4 (1998), 32-38.
Ji Young Choi; Luz Maria DeAlba; Leslie Hogben; Benard M. Kivunge; Sandra K. Nordstrom; Mike Shedenhelm
The nonnegative P_0-matrix completion problem,
Electron. J. Linear Algebra 10 (2003), 46-59.