appellants’ counsel to review the answers to the interrogatories after their completion, and allowing appellants’ counsel, if he deems it necessary, to thereafter notice an oral examination of plaintiff limited to the material and necessary information not adequately supplied through the answers to the interrogatories; and (3) deleting therefrom the provision which granted that branch of plaintiff’s motion which requested priority in conducting an examination before trial and by substituting therefor a provision denying said branch of the motion. As so modified, order affirmed insofar as appealed from, without costs or disbursements. The answers to the interrogatories are to be served upon the appellants within 30 days after service upon the plaintiff of a copy of the order to be entered hereon, with notice of entry. The underlying action was commenced by the plaintiff, NOPA Realty Corp., the corporate owner of property occupied by a hospital, against a caterer, Central Caterers, Inc., and two individual defendants, Murray and Milton Berg. The gravamen of the action is that the defendants made secret illegal payments to Dr. Anton Notey, the former president of the corporate plaintiff, in connection with a lease negotiated and executed in 1972 by the Bergs and Dr. Notey on behalf of the corporate defendant and corporate plaintiff, respectively. Under the circumstances of this case, Special Term properly ordered Interrogatory No. 7 stricken since appellants have not made the strong showing of necessity and desirability required to obtain the disclosure of plaintiff’s Federal and. State income tax returns
(Gottlieb v Friedman, 42 AD2d 965 ;
Glenmark, Inc. v Carity, 22 AD2d 680 , app dsmd
15 NY2d 956 ). However, Special Term erred in granting that branch of plaintiff’s motion which was to strike certain other of appellants’ interrogatories since they are material and necessary to the defense of the instant action (CPLR 3101, subd [a];
Allen v Crowell-Coilier Pub. Co., 21 NY2d 403 , 406). Special Term also erred by requiring the completion of oral examinations by all parties prior to the submission of responses to appellants’ interrogatories. Appellants originally required plaintiff to answer the interrogatories within 15 days of the service of the demand (CPLR 3134, subd [b]). The answers were to be furnished several weeks before the date on which appellants scheduled their original oral examination of plaintiff. Appellants may elect to use both interrogatories and oral examinations before trial as discovery devices. They must, however, invoke one device before the other (see
Katz v Posner, 23 AD2d 774 ), which they have properly done in the instant case. Written interrogatories, which have been utilized by appellants as their initial disclosure device, are a more efficient and economical method of discovery in commercial litigation, involving the activities of various corporate entities and their principals
(Barouh Eaton Allen Corp. v International Business Machs. Corp., 76 AD2d 873 ). In order to regulate the conduct of discovery in the most efficient manner to minimize duplication, appellants’ counsel should initially review plaintiff’s answers to the interrogatories. If the required information is not supplied through the answers to the interrogatories, then appellants’ counsel may schedule an examination before trial of the plaintiff (see
Barouh Eaton Allen Corp. v International Business Machs. Corp., supra). Finally, Special Term erred in granting that branch of the plaintiff’s motion which requested priority in conducting an examination before trial of the appellants. Since appellants served their notice to examine plaintiff within the time to answer, it had priority in conducting an examination before trial (CPLR 3106, subd [a];
Buzzell v Mills, 28 AD2d 674 ). This normal priority is only reversed in actions alleging a breach of a fiduciary relationship between the parties, usually arising from a business enterprise involving both the plaintiff and defendant, in which the pertinent facts are wholly within the knowledge of the defendant (see, e.g.,
Halitzer v Ginsberg, 80