I am ranking on 9th spot for a keyword whenever I build some HIGH PR backlinks I get on top spot for a day or 2 then roll back to a spot around 10th spot 7 websites are authority websites and my ranking is still better than many other authority websites. domain authority of above 7 websites is 60 and above mine is 30 page authority is below 20 for all these sites mine is 35. some sites with domain authority 60 and above are ranking under me. how do I get better ranking permanently or for longer period? any suggestions? please help?