What need I read to understand this paper?

Economics Economics Questions
1

I found this paper critiquing AD/AS:

Link

However, I do not have a good enough grasp on the concepts discussed to understand it.

For example, the IS/LM theory and the labor market theory of output.

What good text can you recommend that covers AD/AS?

I’d like to be able to understand this critique of the model (I’m also looking at Austrian critiques as well).

Thanks.