Here are entered general works on the concept of sister cities. Works on individual sister cities are entered under the names of the individual cities with appropriate topical subdivision, with an additional entry under the heading Sister cities.
Here are entered works on partnerships between webmasters and merchants in which the webmaster provides links to the merchant's Web site and in return is paid a referral fee for sending visitors to the site or a commission based on sales generated by the referral.
Here are entered works on persons who, in conjunction with sex therapists, serve as intimate partners to persons seeking to improve sexual dysfunction or relationship skills.