I recently came across a book written by two senior scholars in my field (anthropology), who cite a paper I published with a colleague two years ago. They cite us quite favorably and in most places they cite us correctly. However, there are two passages which they have copied verbatim from our paper but without attributing them to us, nor even citing us anywhere on the respective pages.
What should we do about that? We certainly don't want to ruin our relationship. What are appropriate steps to be taken?
We have never met the authors in person but been exchanging emails with one of them a few times – all very positive exchanges. He is also supposed to participate in a conference panel with us this year. How to bring it up and what should we expect from them to do?