If you wish to cite the book, you can use the following tex-code:

\bibitem[Juschenko]{Juschenko:book}
\bibauthor{Juschenko, K.,} (2015).
\newblock {\em Amenability of discrete groups by examples.}
\newblock Current
version available at
\hfil\break {\tt http://www.math.northwestern.edu/\string~juschenk/book.html}.