APA
International Union of Public Transport, IUPT/UITP, . (1991). Green light for towns. Bryssel: International Union of Public Transport.
Chicago
International Union of Public Transport, IUPT/UITP, . 1991. Green light for towns. Bryssel: International Union of Public Transport.
Harvard
International Union of Public Transport, IUPT/UITP, . (1991). Green light for towns. Bryssel: International Union of Public Transport.
MLA
International Union of Public Transport, IUPT/UITP, . Green light for towns. Bryssel: International Union of Public Transport. 1991.