Own motion reopening by Appeals Council limited to 60 days; reopening after 60 days allowed only on the motion of claimants. Court gives considerable deference to an agency's interpretation of its own regulations,and construe the provisions of the relevant regulations and statutes to have cohesive meaning. Where only declaratory and injunctive relief sought, plaintiffs not required to identify class members once the existence of the class has been demonstrated. Courts have broad discretion to grant or deny class certification. Class certification issue remanded where plaintiff's lack of evidence supporting class certification was due to defendant's failure to respond to discovery requests.