I liked the mentioned article by Massey very much too, but I guess the best descriptions are still Deligne's SGA 7,part II, chapters 13, 14, where he even draws some figures. I found Wall: <a href="http://wwwhomes.uni-bielefeld.de/triepe/Wall.pdf" title="Wall's BAMS survey">"Periods of Integrals and Topology of Algebraic Varieties"</a>, Griffiths <a href="http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&handle=euclid.bams/1183531477" title="Griffiths summary">"summary"</a>
and his <a href="http://www.numdam.org/numdam-bin/fitem?id=PMIHES_1970__38__125_0" title="Griffiths Periods III">"Periods III"</a>
 very helpfull, parts of this <a href="http://www-fourier.ujf-grenoble.fr/~peters/motivic.f/Tatalects.pdf" title="Peters Tata book">motivic book</a> too. Related to the theme is the local monodromy theorem, about that, monodromy-weight conjecture etc., I found Illusie's article in Asterisque 223 very good.