Not quite on top of the forms
What a pity this piece was marred by the author's muddled thinking in referring to "the sonata" and "sonata form" as one and the same thing.
While it is true that the first movement of the majority of sonatas (and sometimes other movements, too) employ the sonata form, the two terms remain distinct and are otherwise unrelated.
For further enlightenment, readers (and the author) might care to visit the website: http:www.classicalarchives.comdictsonata_form.html
18 North Rock