39. Other than in relation to the sale and purchase of the clientele of a member or of a partnership or company, a member engaged in the practice of public accounting shall not directly or indirectly pay to any person who is not in the practice of public accounting a commission or other compensation to obtain a client, nor shall he accept directly or indirectly from any person who is not in the practice of public accounting a commission or other compensation for referring the products or services of such person to a client.