Cite the author's last name, year of publication and page number parenthetically within the text the first time that you cite a source. For example:
Some observers believed that birds were "eaters of souls" (Smithson, 1543, p. 346).
Split your initial citation if you have mentioned the author by name in your text. In this case, the year should be cited parenthetically following the author's name, and the page number should be cited parenthetically directly following your quotation. For example:
Contemporary historian Smithson (1543) observed that birds were "eaters of souls" (p. 346).
Omit the year of publication from subsequent citations of the exact same source. For example:
Many of the pious argued that rooks should "bee scourged of the earth" (Smithson, p. 349).
Smithson further argued that rooks should "bee scourged of the earth" (p. 349).