Cite the author name, year of publication and relevant page if applicable in parentheses for an in-text citation in APA style. Cite all authors of the source in the first citation and the first author only in any subsequent citations if your source has three to five authors. Cite the first author only if your source has more than five authors. For example, in a work with one author: "The study found no evidence of occlusion (Vile, 2001, p. 7) ..."; "In Kepler (2011) we find ..." In a work with three authors: "Rye, Weeks and Devo (2007) suggest ... Rye et al. (2007) further suggest ..." In a work with more than five authors: "Miller et al. (2001) stated ..."
Cite the author's name, the date of publication and a page number if applicable in a parenthetical citation in Chicago/Turabian style. Use only the first author's name followed by "et al." if there are more than four authors. Use the initials "n.d." if your source is undated. For example, in a work with one author: "This was admitted as a fact before the court (Delly 1999, 17)." In a work with more than four authors: "The measurement of adequacy was not declared (Since et al. 2003, 13-15)." For a work with no publication date: "I cannot surrender to the adventitious loss of my identity (Riger n.d., 3)."
Cite the author's name followed by a page number in a parenthetical citation in MLA style. Do not place a comma after the author's name. For example, "A lawyer for the defense called attention later to the omission (Alley 10)."