^European Union law after Maastricht: a practical guide for lawyers outside the common. The Union has two primary types of legislative acts, directives and regulations
^Steiner، Josephine؛ Woods، Lorna؛ Twigg-Flesner، Christian (2006). EU Law (ط. 9th). Oxford: Oxford University Press. ص. 56–60. ISBN:978-0-19-927959-3.
