The basic textbook employed by the Defense Institute of Security Cooperation Studies (DISCS - formerly DISAM) for instruction of all classes covering the full range of security cooperation activities. The text is revised annually and commonly referred to as the Green Book as it is bound in a green cover.
7938 Passenger Train is a City Trains set released in June 2010. It was sold in the US as a Special Edition set at the LEGO Store and Toys R Us.
Lego has also released accompanying products branded under the Friends theme. These include a picture frame which includes 49 Lego elements which is available from Lego brand stores and a display stand which includes 17 elements that was released as a promotional polybag.