Notes
1. Ulrich's™ is the authoritative source of bibliographic and publisher information on more than 300 000 periodicals of all types academic and scholarly journals http://www.ulrichsweb.com/ulrichsweb/
2. The Web of Knowledge Service for the UK Education provides a single route of access to Thomson Reuters's products subscribed to by an individual institution www.wok.mimas.ac.uk/. Note that many science papers also use the term transport, hence the differences in the numbers from the two search criteria.