Essential readings on Customs administration

There are a number of readings on international trade.  However, there are not many readings on Customs administration.  Even they are not well organized either.  Professionals who study Customs administration are a few.  They have difficulty in locating good readings on Customs administration.  Here  I am going to list good readings regarding Customs administration from my perspective.  Some are just short blogs or newspaper articles and some are journal articles and books.  Some are recommended by my colleagues and some are located by me.

• Who profits from trade facilitation initiatives?
  www.voxeu.org/article/who-profits-trade-facilitation-initiatives