Ninteen Supermodels: Here is a large scan of the 1968 Glamour magazine article.
These 19 models are not the only ones who were considered supermodels at the time but it is a good representation.
BELOW CHERYL TIEGS, LISA PALMER, VERUSCHKA
TWIGGY, SUNNY HARNETT, SUE MURRAY
MARISA BERENSON, HEIDE WIEDECK, IRIS BIANCHI, GRETCHEN HARRIS
JEAN SHRIMPTON, KATHY CARPENTER, JEAN PATCHETT
PICTURES OF THE NINETEEN SUPERMODELS