Ind. R. Prof'l. Cond. 7.5
[1] A firm may be designated by the names of all or some of its members, by the names of deceased members where there has been a continuing succession in the firm's identity, or by a trade name that complies with the requirements of the Rules of Professional Conduct. A lawyer or law firm may also be designated by a distinctive website address or comparable pro-fessional designation. The use of a trade name in law practice is acceptable so long as it is not misleading and otherwise complies with the requirements of paragraph (a)(4). A firm name that includes the name of a deceased partner is, strictly speaking, a trade name. The use of such names to designate law firms has proven a useful means of identification. However, it is mis-leading to use the name of a lawyer not associated with the firm or a predecessor of the firm, or the name of a non-lawyer.
[2] With regard to paragraph (d), lawyers sharing office facilities, but who are not in fact associated with each other in a law firm, may not denominate themselves as, for example, "Smith and Jones," for that title suggests that they are practicing law together in a firm.