@inbook{EButler+1974+xiii+xxii,
url = {https://doi.org/10.4159/harvard.9780674434165.intro},
title = {Introduction},
booktitle = {Theory of International Law},
author = {William E. Butler},
publisher = {Harvard University Press},
address = {Cambridge, MA and London, England},
pages = {xiii--xxii},
doi = {doi:10.4159/harvard.9780674434165.intro},
isbn = {9780674434165},
year = {1974},
lastchecked = {2026-05-11}
}