APA
Frans Pennings, Blanpain R. & Opstal M. (1999). Social security law : Supplement 30 case law. : Klumer Law international P.O. Box 322 3300 AH Dordrecht.
Chicago
Frans Pennings, Blanpain R and Opstal M. 1999. Social security law : Supplement 30 case law. : Klumer Law international P.O. Box 322 3300 AH Dordrecht.
Harvard
Frans Pennings, Blanpain R. and Opstal M. (1999). Social security law : Supplement 30 case law. : Klumer Law international P.O. Box 322 3300 AH Dordrecht.
MLA
Frans Pennings, Blanpain R and Opstal M. Social security law : Supplement 30 case law. : Klumer Law international P.O. Box 322 3300 AH Dordrecht. 1999.