Anyone interested in the role played by the Golden Snidget in the development of the game of Quidditch is advised to consult Quidditch through the Ages by Kennilworthy Whisp (Whizz Hard Books, 1952).
-- Newt Scamander, Fantastic Beasts (FB)
Whizz Hard is a deliberate over-pronunciation of the two syllables of the word "Wizard".
The later editions of Quidditch Through the Ages do not necessarily include the Diagon Alley address of Whizz Hard Books, as originally printed on the Comic Relief edition title page in 2001.
Lexicon list of Publishers and Publishing
From the Web
Harry Potter Wiki: Whizz Hard Books