The abbreviation “ff.” should not be used, but inclusive numbers specified.
The last two digits should always be repeated. Examples:
- 13–15, 132–34, 132–43, 132–235, 132 f.
- 1984–86
- 7,000–8,000 should be written, thus not 7–8,000.
In German and the Scandinavian languages complete numbers may be written out, e.g.: 132–134, 132–143; 1984–1986