For data about population, age, sex, dwellings, families, marital status and language.
For data about immigration and ethnocultural diversity, aboriginal peoples, education and labour, mobility and migration, language of work, income and housing.
The Purdue OWL is an amazing online resource for APA, MLA, and Chicago citation and style questions.
The Cornell University Library provides helpful APA and MLA citation guides.
The Simon Fraser University Library provides resources for APA (including Business and Government resources), MLA, Chicago, and others (CSE, ASA, IEEE, etc.) This is also a great resource for information on citing Canadian government documents and statistics.