PRACE DOKTORSKIE - DANIA 290,771 FIEHN NILS-ERIK Small-sized oral spirochetes and periodontal disease : [thesis] / by Nils-Erik Fiehn ; Department of Microbiology Royal Dental College Copenhagen. -Copenhagen : Munksgaard, 1989. - 31 s. : il. ; 28 cm (Acta Pathologica Microbiologica et Immunologica Scandinavica, ISSN 0903-465X ; suppl. nr7, vol. 97 ISBN 87-16-14805-3