IEEE et al. error
According to the IEEE Citation Reference, "et al." should be used when three or more names are given.
In the current version, the IEEE style in Zotero does not generate et al. for more than three authors. It should be corrected.
In the current version, the IEEE style in Zotero does not generate et al. for more than three authors. It should be corrected.
(if you're reporting errors in styles, please always cite a specific section or page number of the official style guide)
For three or more authors: ANDERSEN et al.: DYNAMICAL MODEL OF DC WAVEGUIDE LASERS
9 and 36
and some examples on different parts of the document.
Apparently, IEEE allows cap authors.