HULLEY S.B, . (2007). DESIGNING CLINICAL RESEARCH + ONLINE. : LIPPINCOTT WILLIAMS & WILKINS.
HULLEY S.B, . 2007. DESIGNING CLINICAL RESEARCH + ONLINE. : LIPPINCOTT WILLIAMS & WILKINS.
HULLEY S.B, . DESIGNING CLINICAL RESEARCH + ONLINE. : LIPPINCOTT WILLIAMS & WILKINS. 2007.