Go to the other website and look ? :) or search string = *the part between the two* this goes in the search box *site:(otherwebsitename)(name of yoursite or recip text )*..
like this.. below
If the words,phrase, or anchor text, or your site name are there on the other site, this will find them ..and tell you the page(s)..then you go to the page(s), and see if they are linked..then look in the source code(s), to see if they were "nofollow" or not..
Obviously you don't leave on the *at the beginning, nor the* at the end..
You can never find all the sites that link to you, because the search engines won't show all of them ..but
search string="example.com" or search string="www.example.com"
Will get you most of those who are linking to your home page..
search string="example.com/page" or search string="www.example.com/page"
This time you leave the "at the beginning and at the end" ;)
Will get you most of those who are linking to a specific page..change what is the part of the string at "page" accordingly..You are basically searching for mentions of specific URLs..but not all of results returned will actually be linked..some may just be talking about the URL(s) you are interested in.
There are other ( more complex and more efficient..and involving coding / apis ) ways of doing these enquiries..but they still won't deliver 100% of the sites that are linking to you ( especially if you have a very large number of links to you )..but as you are asking, the means of doing them would probably be beyond where you are..and more than likely "overkill" for what you are doing ATM..
There are also sites and software etc, that will tell you who is linking to you..but never with guaranteed 100% accuracy..