I saw this yesterday in an online news story.

Problem:
A period is missing.

Explanation:
There are three Latin phrases that mean and others:

• et alii — spelled E-T followed by A-L-I-I — which is masculine;
• et aliae — spelled E-T followed by A-L-I-A-E — which is feminine;
• et alia — spelled E-T followed by A-L-I-A — which is neuter.

The correct abbreviation of any of the three Latin words for “others” requires a period after A-L.

An example of proper use is “the report presented by Jones et al.” (notice the period after A-L).

Solution:
“et al.”