"have so far established" is a grammatically correct and commonly used phrase in written English.
It is often used to convey that something has been accomplished or proven to be true up to a certain point in time. Example: "Our research team have so far established a strong correlation between diet and heart disease, but further studies are needed to fully understand the exact connection."
He is satisfied with demonstrating that all we, the philosophers, have so far established, does not hold.
Reported data have so far established Rer1p as a limiting factor in initial complex assembly of γ-secretase.
Many studies have so far established that transport costs have serious implications for the accessibility of health care for the people in need [ 29– 31].
We have so far established that by means of a competitive logic as a motivation, students playing the game in schools are encouraged to work towards a state of health and a better self in terms of an ideal body.
Nevertheless, reports of thermographic analyses have so far established that the thermal pattern and symmetry of the body are more important than the absolute temperature for diagnosing disease [ 11].
It was as though the designer had used everything he has so far established — the models gracefully walking the stage, a sense of modesty (with pants under coats and skirts).
"Chinese high-speed rail has so far established a mortality-risk level that equals or exceeds that of the world's safest airlines," Mr. Barnett wrote in an e-mail.
Mr. Freitas, the District Attorney, said that the investigation begun three weeks ago into possible voting irregularities involving temple members had so far established that no such allegations had been brought to the attention of his office during Mr. Stoen's tenure there.
Ethiopia has so far established several protected areas, which cover about 16.4% of the total area of the country (Tessema et al. 2010).
Mr. Lind, an entrepreneur who in 1997 founded Strategic Partners, an emerging markets corporate finance firm specializing in telecommunications and finance, has so far established InQbiz incubators in Bombay, India, and Cape Town, South Africa.
