Edgar N. Gilbert. Line-of-sight paths over random terrain. Bell Syst. Tech. J., 54(4):735-765, 1975. [doi]
@article{Gilbert75,
title = {Line-of-sight paths over random terrain},
author = {Edgar N. Gilbert},
year = {1975},
doi = {10.1002/j.1538-7305.1975.tb02863.x},
url = {https://doi.org/10.1002/j.1538-7305.1975.tb02863.x},
researchr = {https://researchr.org/publication/Gilbert75},
cites = {0},
citedby = {0},
journal = {Bell Syst. Tech. J.},
volume = {54},
number = {4},
pages = {735-765},
}