Secondary school biology achievement related to class period length and teaching method
By: by Roger Gale Olstad.
Number of pages: 230
Subjects: Biology -- Study and teaching (Secondary); Science -- Study and teaching (Secondary)
Notes: Microfilm of typescript. Ann Arbor, Mich. : Univerity Microfilms, [1963?] -- 1 reel ; 35 mm. (63-7945)

Thesis (Ph.D)--University of Minnesota.

Bibliography: leaves 144-148.