Stationing guards in rectilinear art galleries
H. Edelsbrunner, J. O’Rourke, E. Welzl, Computer Vision, Graphics, and Image Processing 27 (1984) 167–176.

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 structure and maintenance of hybrid zones as exemplified by Podisma pedestris
G. Hewitt, N.H. Barton, in:, R. Blackman, M. Ashburner (Eds.), Insect Cytogenetics, Wiley-Blackwell, 1980, pp. 149–170.