Here’s a digitization of the first one and the second one, including a picture of an edition of the work itself. I found it by googling the names of the works in the quoted section.
If that’s not sufficient, I suggest you ask at your local (or most local) university library.
It being listed in the catalog would at least be some indication that the evidence exists, as opposed to an endless linked list of “trust me bro”.
Here’s a digitization of the first one and the second one, including a picture of an edition of the work itself. I found it by googling the names of the works in the quoted section.
If that’s not sufficient, I suggest you ask at your local (or most local) university library.
you are doing god’s work with the patience of a saint