Grammar, Usage / Citing a source for racism and death penalty for black men who raped white women in the South [3]

Hi there, i desperately need help citing a source in MLA 7th for my essay. I can't post the link for it so i took out a sentence out from the pdf file so if googled only the correct source appears:

"The scourge of racial bias continued unabated through much of the 20th century, when black men convicted of rape in the South received deathsentences in grossly disproportionate numbers"

I'm sorry if this is the wrong place to post this, but I'm really lost and really need to cite this source. Any help will be greatly appreciated