In NLRB v. Interboro Contractors, Inc., 388 F.2d 495, 500 (2d Cir. 1967), the Court of Appeals for the Second Circuit stated that the efforts of an individual employee acting alone to enforce the provisions of a collective bargaining agreement may be deemed "concerted," and thus protected, at least when the individual's interpretation of the agreement has a reasonable basis.
In Behring International v. NLRB, supra, we held that the Board's rule shifting the burden of proof to the employer to show a legitimate reason for a discharge once a prima facie case had been made out of a discharge for engaging in protected activity was inconsistent with section 10(c) of the National Labor Relations Act, 29 U.S.C. ยง 160(c) (1976).