RT Journal Article SR Electronic T1 Surface ultrastructure of giardial infestation JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 296 OP 299 VO 43 IS 4 A1 Raymond R. Tubbs A1 William A. Hawk YR 1976 UL http://www.ccjm.org/content/43/4/296.abstract AB