This sort of empirical testing is very tricky indeed, which undoubtedly explains why so little work has been done in just this area. (religion-online.org)
Although it has a few rough edges you can clearly tell a lot of work has been done on the game. (armillogame.com)
A lot of work has been done on making nanoparticles, less work on nano delivery systems. (treehugger.com)