This article from the Boston Globe gives an excellent description of what running Boston last Monday was like, and why we keep coming back, almost regardless. The writer, for whom it was the fifth Boston and ninth total, expresses the range of emotions, expectations, frustrations, excitements, ups, downs, ... all of which form the challenge of racing a marathon in general, and...

Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).