TIP:
Use + and - before your keywords to match only pages with (or without) the words in them.
For example, "+Eritrea -Asmara" will match all the pages with "Eritrea" and without "Asmara".

You can require an entire phrase by putting it in quotation marks: eg. "Ghebrehiwet the crook".

To require or prevent pages with phrases, put a +/- outside the quotation marks: eg. +"United Nations" or -"United Nations".