Is Oxford University Press going out of business?
The formal recognition of the University of Oxford's right to print its own books came in 1586 and today, Oxford University Press (OUP) it is the largest university press in the world. However, after centuries of print tradition, it will finally be closing its sole surviving printing arm.
Is Oxford University Press a credible source?
Oxford University Press holds the trademarks on both the book series you mention. Oxford definitely is a reputable press and a lot of energy and attention goes into their Reference publications.