includes illustrations, one must ju

includes illustrations, one must judge their quality and relationship to the text. Recent
reference publishing has placed increasing emphasis on visual material. 25 Print
sources have the advantages of being straightforward to use, predictable in cost, and
usable by more than one person simultaneously if produced as a multivolume set.
Disadvantages include the space required to house print sources, the problem in
maintaining their currency, and the limitations on search strategies.
Microform formats may prove satisfactory for sources with short entries and
alphabetical arrangements, such as bibliographies and directories. Microforms can
save space and are a recognized medium for preserving content that has continuing
value. Disadvantages include equipment costs and maintenance, the need for user
orientation, the limit to one user at a time per microform viewer, and the limitations
on search strategies.
CD-ROMs allow complex searching and store large amounts of information. The
introduction of multimedia CD-ROMs and DVD technology means that they now can
store images and sound in addition to text and numerical data. 26 (As with illustrations
in print sources, the quality and reference value of such images and sound should be
assessed.) On the other hand, CD-ROMs may be expensive, somewhat slow to search,
and variable in ease of use because interfaces are not standard. They may lack currency,
and they require work space for equipment.
Like CD-ROMs, online databases and Web resources support flexibility and
complexity in searching and may contain large amounts of information. In addition,
they can be updated more frequently than CD-ROMs. Limitations of online access
to commercial databases include unpredictable costs (unless databases are locally
loaded or licensed to allow unlimited use), the need for equipment, and the frequent
need for special training to use search systems effectively. Web resources may vary
in usability and stability. These advantages and disadvantages must be weighed when
evaluating a reference source in one or more formats.