Consistency of $\mathfrak{b}<\mathfrak{s}$

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I'm reading a paper written by Vera Fischer and Juris Steprans related with cardinal invariants of the continuum where they obtain, using finite support iteration of c.c.c partial orders, a model where $\mathfrak{b}=\kappa<\mathfrak{s}=\kappa^+$.

In the introduction of that paper, they say that there exists an alternative proof, given by Jörg Brendle, where he obtain a model with $\mathfrak{b}=\omega_1<\mathfrak{s}=\kappa$ with $\kappa$ regular. I want to see this proof but I can't find the referenced article (It is called "how to force it, lecture notes").

Does someone knows where to find this proof?

Thanks for advance.

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I had the opportunity to ask him personally today. The result you mention has not been published, but the good news is that the result is outdated: in the paper "Mad families, splitting families and large continuum" it is proved by Brendle and Fischer that $\kappa=\frak b<\frak s=\lambda$ is consistent for any regular uncountable cardinals $\kappa<\lambda$.