X -- The Problem of the Negro as a Problem for Thought Fordham University Press, 2013
X and the City: Modeling Aspects of Urban Life Princeton University Press, 2012
The X-15 Rocket Plane: Flying the First Wings into Space University of Nebraska Press, 2013
Xunzi: Basic Writings Columbia University Press, 2003PRIMARY SOURCE
A primary source is a work that is being studied, or that provides first-hand or direct evidence on a topic. Common types of primary sources include works of literature, historical documents, original philosophical writings, and religious texts.
The XYZ of Psychoanalysis: Epilogue to a Great Beginning Praeger Publishers, 1991