@article{SOSP-J-1975-HabermannFC76,
	author        = "A. Nico Habermann and Lawrence Flon and Lee W. Cooprider",
	doi           = "10.1145/360051.360076",
	journal       = "{Communications of the ACM}",
	number        = 5,
	pages         = "266--272",
	publisher     = "{ACM}",
	title         = "{Modularization and Hierarchy in a Family of Operating Systems}",
	volume        = 19,
	year          = 1976,
}