On the Orbital Periods of Two Bona-fide lambda Bootis Stars HD 64491 and HD 141851 Iliev, I. Kh. ; Paunzen, E. ; Barzova, I. ; Andrievsky, S. M. ; Chernyshova, I. V. ; Kamp, I. Abstract Publication: Information Bulletin on Variable Stars Pub Date: September 2001 Bibcode: 2001IBVS.5178....1I