How were you able to convince the publisher to let you put up an online version for free? Also, please collect data regarding whether this harms book sales. If

How were you able to convince the publisher to let you put up an online version for free? Also, please collect data regarding whether this harms book sales. If it turns out not to have any significant effect, then this could be cited as evidence in any future circumstance where someone is trying to convince a book publisher to approve of releasing an online version of a book.