A. Implied in your question is that you have attached your cover letter to your email as a separate file just as you did your resume. If you do that, I can give you no advice about how to get it read because, frankly, I refuse to read a second attachment and go right to the file that suggests it is the resume.
Even if I make a mistake and open the wrong file, I immediately close it and go to the next one–the resume file.
BTW, don’t enclose a file that suggests that it is a reference list and send it to a 3rd party recruiters; your references will not be called except to source for job leads or late in the search when they are legitimately needed for references. Why risk annoying a reference?
Instead of emailing a separate file, use the message area of the email that you are attaching your resume to send a cover letter. Most people I know do read those so you can get your message across there.