Forty-five reference types are already defined (such as Journal Article, Book, Conference Proceedings, etc.). Three additional Unused reference types are available so you can define your own.
How can I do it ? I could not figure it out.
Help says:
The fields (Author, Title, Year, etc.) displayed for each reference type can be modified or deleted. New fields can also be added, up to a total of 52 fields per reference, including the reference type name.
Modified from Help (X2): Adding and Deleting Reference Types
There are three Reference Types titled Unused, where you can define a new type of reference. If these are already in use, you can overwrite other reference types that you do not need in order to create new reference types. For example, if your subject area never involves art, you may have no use for the Artwork reference type; you could replace it with another reference type.
To add a new reference type:
From the Edit menu, choose Preferences, select the Reference Type option in the list of preferences, and click Modify Reference Types to open the Reference Types preference.
Use the drop-down list at the top to select one of the Unused reference types. If all of the “Unused” reference types are in use, select a reference type that you are willing to overwrite.
Type a name for that new reference type into the column heading.
Note : A reference type must have fields defined in order to appear in the reference type list for new or existing references. If you simply change the name of an Unused reference type, it will not appear in your reference type list. You must also include fields in the reference type as described next.
Continue down the column for that reference type, adding new fields as necessary. (Delete or rename unwanted fields if you are overwriting another reference type.) Remember to match the meaning of the fields you add with the Generic row headings. It is often helpful to use the other reference types as guides, too.
Click OK after you have added all of the necessary fields, and you will return to the main Preferences window for Reference Types.
Click OK Save to save your changes.
You can now use this new reference type when entering references. You should also edit your styles so that they correctly reflect the type of format required for this new reference type. If you overwrite an existing reference type, any references that used the old reference type will change to use the new reference type.
Note : If you ever plan to use journal articles in your library, do not overwrite the Journal Article or Electronic Article reference types. These two reference types are the only ones for which Journal Abbreviation replacements can be made with the Journals Term List.