Writer required for long-term work writing website articles

Looking for a blogger that is confident of
* Researching a particular topic to the point that there is nothing else to know about it on the internet
* Summising into own words (No way can copied content be used)
* Creating articles and posts of authority, maybe 2,000 words up

Am looking to work with someone long-term. Minimal hours to suit and flexible on timing. Have a number of websites so also good to be adaptable to be a knowledge expert on any number of subjects.