Are links with additional info to product allowed in ebay member to member messages?

[kontrolsports!]

I often get customers asking me detailed information on the watches we sell, questions like how do I choose between this model or that?  Can I use links to a blog or website to help them get the info they need so they can make a decision.  The links are not to my own webpage of course and also not to other peoples webpages that have items for sale.  Information only links. Some examples are: bloggers who describe in detail how the water resistence rating is deduced, or information on how lume works and what to expect, or detailed info on different models of watches (year made, some history, specifics etc).  I don't want to fall foul of what is and what isn't allowed through ebay messages.  I've searched ebay help and found very little info on this subject.  Thanks for any light you can shed for me.