The phrase "authoritative on" is correct and usable in written English.
You can use it to refer to someone who has a great degree of knowledge and skill in a certain area. For example, "My boss is quite authoritative on the subject of marketing strategies."
Squidoo shares little in common with any of the services above because no one person can really be authoritative on a given topic.
"A good blogger is passionate and authoritative on something.
Hers is the first generation of women architects comfortable about being womanly and authoritative on the job.
Not Holloway, though: he shows no favouritism to the various branches of the Christian family and is just as authoritative on Islam as he is on Anglicanism.
"The Complete and Authoritative Guide to Caring For Your Baby and Young Child" was neither complete nor authoritative on the subject.
Leon Botstein — the furiously multitasking president of Bard, co-director of the festival, and music director of the American Symphony, the resident festival orchestra — is less authoritative on the podium.
The need for high-quality, authoritative, on-the-ground reporting and analysis from around the world has never been greater.
Fortunately, Joey emailed me to give an authoritative take on things.
(Alexander Nazaryan recently wrote about Bamford, who has published four authoritative books on the N.S.A., on Page-Turner).
All of us regularly find ourselves expected to come up with authoritative reports on complex issues on which we lack any authoritative personal expertise.
Twitter User Rank (TURank) [6] is an algorithm which utilizes ranking algorithms to define authoritative actors on Twitter, based on link analysis.
