Hybrid zones and speciation
N.H. Barton, G. Hewitt, in:, W. Atchley, D. Woodruff (Eds.), Evolution and Speciation, Cambridge University Press, 1981, pp. 109–145.

The genetic basis of hybrid inviability between two chromosomal races of the grasshopper Podisma pedestris
N.H. Barton, G. Hewitt, Heredity 47 (1981) 367–383.

A chromosomal cline in the grasshopper Podisma pedestris
N.H. Barton, G. Hewitt, Evolution; International Journal of Organic Evolution 35 (1981) 1008–1018.

The width of the hybrid zone in Caledia captiva
N.H. Barton, Heredity 47 (1981) 279–282.

On the intersection of Orthogonal objects
H. Edelsbrunner, H. Maurer, Information Processing Letters 13 (1981) 177–181.

A space-optimal solution of general region location
H. Edelsbrunner, H. Maurer, Theoretical Computer Science 16 (1981) 329–336.