There are slides devoted to this topic: Lecture 6b, pp. 35-47.
Read the “Howard Aiken” page from the Computer History Museum to find information on Aiken, as well as photographs of artifacts related to the Mark computers.
For a longer article, look at the “Biography of Howard Aiken” on the History of Computers. After, travel to “The Mark Computers of Howard Aiken,” on the same site, for detailed information on Aiken’s technological achievements.
Watch a five-minute video of Aiken narrating footage of the Mark II in operation, explaining its use as we watch others operate it.
Campbell-Kelly and Aspray, Computer: A History of the Information Machine, 59-65
Read Makin’ Numbers: Howard Aiken & the Computer, edited by I. Bernard Cohen and Gregory W. Welch. This compilation of articles features primary and secondary sources on Aiken and the Mark computers.