APA
Blanpain R., van Opstal M., . (1999). Social Security Law : Supplement 26 Bulgaria. The Hague, London, Boston: Klumer Law international P.O. Box 322 3300 AH Dordrecht.
Chicago
Blanpain R, van Opstal M, . 1999. Social Security Law : Supplement 26 Bulgaria. The Hague, London, Boston: Klumer Law international P.O. Box 322 3300 AH Dordrecht.
Harvard
Blanpain R., van Opstal M., . (1999). Social Security Law : Supplement 26 Bulgaria. The Hague, London, Boston: Klumer Law international P.O. Box 322 3300 AH Dordrecht.
MLA
Blanpain R, van Opstal M, . Social Security Law : Supplement 26 Bulgaria. The Hague, London, Boston: Klumer Law international P.O. Box 322 3300 AH Dordrecht. 1999.