Links: Functional programming ebooks

In a subscribe Spb Haskell User Group I've met several interesting links to files garbage with books on the functional programming.

I've dig out Introduction to Functional Programming by Mike Gordon. Judge by the first chapter a lot of text and samples but less mathematics is expecting further. Such a real programmers book.

I do not understand somehow what do they want...

Find an example to show that if V₁=V₂ then even if V₂ is not free in E₁ it is not necessarily the case that
(\V1 V2.E)E₁E₂ = E[E₁/V₁][E₂/V₂]