"For me the noise of time is not sad: I love clocks, watches - and I recall that at first photographic implements were related to techniques of cabinetmaking and the machinery of precision: cameras in short were clocks for seeing..."
A PDF of this article may be downloaded here.
A book chapter from The Landscape of 9/11: A Photographer's Journey may be downloaded as a PDF here. The chapter, Bearing Witness: Memorial Murals in Belfast and Bethlehem, is primarily about the practice of documentation.
Another way to access some of these articles and other material is here.