Measures of public opinion, past and present: interviews, public opinion polls, questionnaires, and surveys (Gallup poll; surveys carried out by other organizations; self-administered poll, survey, questionnaire, or interview – creating your own instrument for data collection allows you to ask questions specific to the issues you seek to understand in your research)
News sources recording events and reactions to events as they occur: historical newspapers, political cartoons, newspaper advertisements; transcripts of television broadcasts