Parenthetical (two authors): (LastName1 & LastName2, Year)
Narrative (two authors): LastName1 and LastName2 (Year)
Two authors with page (if quoting): (LastName1 & LastName2, Year, p. PageNumber)
Narrative with page (if quoting): LastName1 and LastName2 (Year, p. PageNumber)
Multiple citations in one parenthetical (two authors each): (LastName1 & LastName2, Year; LastName3 & LastName4, Year)