The Calculus of Communicating Systems, also known as CCS, is a process calculus introduced by Robin Milner circa 1980.
Milner, Robin. 1980. A Calculus of Communicating Systems. Vol. 92. Lecture Notes in Computer Science. Berlin, Heidelberg: Springer Berlin Heidelberg. https://doi.org/10.1007/3-540-10235-3.
@book{milner_calculus_1980,
address = {Berlin, Heidelberg},
series = {Lecture {Notes} in {Computer} {Science}},
title = {A {Calculus} of {Communicating} {Systems}},
volume = {92},
isbn = {978-3-540-10235-9 978-3-540-38311-6},
url = {http://link.springer.com/10.1007/3-540-10235-3},
publisher = {Springer Berlin Heidelberg},
author = {Milner, Robin},
year = {1980},
doi = {10.1007/3-540-10235-3}
}