In Struggle: SNCC and the Black Awakening of the 1960s. Cambridge: Harvard University Press, 1995. Collier-Thomas, Bettye, and V. P. Franklin, eds. Sisters in the Struggle: African American Women in the Civil Rights-Black Power Movement. New York: New York University Press, 2001. Dudziak, Mary. Cold War Civil Rights: Race and the Image of American Democracy. Princeton: Princeton University Press, 2002. Gilmore, Glenda.
No, an X-ray is not a mechanical wave. An X-ray is an electromagnetic wave. However, in polar molecules, an X-ray can cause the molecule to vibrate rapidly, just like a microwave oven can.
Gamma rays, X-rays, visible light, and radio waves are all forms of electromagnetic radiation. The only difference is the frequency and hence the energy of those photons. Gamma rays are generally the most energetic of these, although a broad overlap with X-ray energies occurs.