Which books / John brought what

I found some weird word choices in my syntax book.

ex1) We have to read which books and some papers.

Here, I suppose, the word "which" is used to give an example that the sentence given below is erroneous.

-> Which books do we have to read [NP[NP___] (and) [NP some papers]]? (NP = noun phrase)

I don't say that word(which) used is wrong because it is chosen to make the point.

What I'd like to know is....

1. Isn't a word 'certain' or 'some' more appropriate in the sentence? (in a normal context or whatever)

[We have to read certain(or some) books and some papers]

ex2)He believed the rumor that John bought what.

In the same way, I suppose, the word "what" is used to give an example that the sentence given below is erroneous.

-> What did he believe [NP the rumor [S' that John bought [NP ___]]]?

2. Isn't a word 'something' is more apporopriate in the sentence?

[He believed the rumor that John bought something]

2 questions^^; (1,2)