21.   Multiple screens can offer a range of sources and screens could also include questions and exercises, historical information, or secondary sources as well as primary source material.

22.   Unlike structured databases, Viewdata is useful for a great variety of written source materials.

23.   Like databases they require source material that is structured in format.

24.   Books or packs which offer compilations of primary source materials have also become more plentiful, including those produced by local record offices and museums.

25.   Many departments buy a varied selection of relevant books and source material and use these alongside teacher-produced resources.

26.   Computer Aided Learning also places high demands on access to pre-processed machine-readable source materials.

27.   That may be achieved either by retaining formal verification notes or simply by retaining the source material from which the document was produced.

28.   The Lexis search may refer you to source material that you have in your library but it also contains unreported cases.

29.   The compositional differences between the short story and its source material need only be sketched here.

30.   The emphasis is on interpretation and evaluation of a variety of primary and secondary source material.