english.stackexchange.com/questions/121054/which-one-is-correct-et-al-s-or-et-al

The grammatically correct way is "Einstein et al.'s paper", because to indicate possession by a noun phrase in English, the 's should be applied ...

english.stackexchange.com/questions/33304/et-cetera-vs-et-al

I would say there is a definite distinction between the two, in definition and in proper usage. Et cetera, often shortened to etc., means literally ...

blog.apastyle.org/apastyle/2011/02/et-al-when-and-how.html

Feb 4, 2011 ... Writers sometimes use the surname of the first author followed by et al. at the first mention of a work that has three, four, or five authors.

www.grammarly.com/blog/et-al

Even if you don't speak Latin, you should know the two meanings of et al. Learn what et al. is, how to use it, and what mistakes to avoid.

www.e-education.psu.edu/styleforstudents/c3_p28.html

It is important to use these abbreviations literally and to punctuate them correctly. Many writers confuse "e.g." and "i.e.," and many type "et al." improperly or do ...