How to cite this booklet/manual?
Why not use the standard article entry type?


  An article from a journal or magazine. Required fields: author, title, journal, year. Optional fields: volume, number, pages, month, note.


Seems like a magazine with articles from different authors to me. If you would want to cite from one of the articles in the magazine, e.g. the first one, it could simply be:

@article{Farronato2015,
 author = {Farronato, C. and Levin, J.},
 journal = {Global Investor},
 number = {2},
 pages = {06--13},
 title = {{The rise of peer-to-peer businesses}},
 volume = {15},
 year = {2015}
}


Please make sure the citation info is correct before using it though. Quick googling seems to report more than one magazine called 'Global Investor'. Please note that I am also not familiar with this field at all.