The London School of Economics has made a collection of campaigning leaflets from the 1975 and 2016 referendums on the UK’s membership of the common market and EU available online. 
The collection can be browsed by referendum year, affiliation, organisation and subject. There are almost 40 leaflets for the 1975 referendum and over 180 from 2016.
For the 1975 referendum they say:
“After Charles de Gaulle famously vetoed the UK’s decision to join the European Communities (EC), the UK finally became a member in 1973. By 1975 the first ever UK-wide referendum took place, where the electorate were asked “Do you think the United Kingdom should stay in the European Community (the common market)?” with 67% of the voting electorate answering “yes” and 33% “no”.”
The collection is part of a wider archive of documents looking at Britain and the European Union.
The images are not copyright free and are made available for research only.
This collection is not available to search in iDiscover and should be accessed on the LSE website.
Electronic Collection Management 