TY - JOUR A1 - Gerber, T.P. A1 - Cheung, S. T1 - Horizontal stratification in postsecondary education: Forms, explanations, and implications Y1 - 2008 DO - 10.1146/annurev.soc.34.040507.134604 JF - Annual Review of Sociology VL - 34 IS - 1 ER -