The Tipping Point: How Little Things Can Make a Big Difference
Gladwell, Malcolm
Doctor Who and the Keeper of Traken
Terrance Dicks
Doctor Who: Target (37)
Doctor Who, the Highlanders
Gerry Davis
Doctor Who: Target (90)
To Prime the Pump
A. Bertram Chandler
Grimes in Federation Service (3)
Planets of Adventure
Eric Flint & Murray Leinster