An excellent paper from Evert Gummesson. It particularly explores the complexity exemplified in the statement "you don't employ the law firm, you employ the lawyer".
The upshot of this, from a marketing perspective, is that the marketing team cannot take on the task of marketing on their own. They can facilitate and cajole but ultimately the lawyers (in this example) have to do the networking, go to the conference and write the blog posts.
They cannot and should not be entirely shielded from getting people to buy their product.
In a goods-producing firm it is usually quite easy to separate marketing (including sales) from production. You belong either to one or to the other. In a service firm, and especially in a professional service firm, the following dilemma arises: The person who is a marketer of the service usually must also be prepared to take part in the operation of assignments