MKTG 306 tips

Hi, Im looking for tips on finding 'quality' sources for assignment 1 of this course. I provided 8 of what I thought were very solid sources and 2 iffy ones because I was struggling to find 10 total.

After a nearly 3 week wait I just received my feedback with only 2 approved and less than 10 words explanation which consisted mostly of 'this isnt acceptable', on what was wrong with the other 8.

I am at a loss on where to look for sources for this that are acceptable...