In Pittsburgh Glass, the Court held that it was not a denial of due process for the Board to refuse to consider evidence relating to the certification issue when petitioner first sought to introduce such evidence at the unfair labor practice hearing.
In Catholic Bishop of Chicago v. NLRB, 559 F.2d 1112 (7th Cir. 1977), aff'd on other grounds, 440 U.S. 490, 99 S.Ct. 1313, 59 L.Ed.2d 533 (1979), the court concluded that exercise of jurisdiction by the NLRB over labor disputes among parochial school teachers fosters impermissible entanglement.