To deal with root systems of type B C D, one needs to understand symmetric Laurent polynomials $\Lambda$. I am wondering if the naive definition of power sum symmetric Laurent polynomials form a basis in $\Lambda$. More specifically, define $$ p_r = \sum_{i=1}^N x_i^r + x_i^{-r},$$ and define power sum symmetric Laurent polynomial indexed by a partition $\lambda \vdash n$ as $$ p_\lambda = \prod_{j=1}^n p_{\lambda_i}.$$ What are some standard references that talk about the connection of $\Lambda$ with root systems, as well as Macdonald operators? Thanks.

edit: I guess it is obvious that $p_\lambda$ does form a basis, if I restrict to symmetric Laurent polynomials that are also symmetric with respect to $x_i \mapsto x_i^{-1}$. So I would like to change my question to just asking for a reference relating $\Lambda$ with Macdonald operators.