543,711 GERDIE BJORN Leisure and muscular performance in health and disease : a study of 40-64— year-old northern Swedes : Zakademisk avhandling7 / by BjBrn Gerdle ; University of Umea. - Umea : University, 1985. — [6], 40 s., 5 prac : il., wykr. ; 22 cm + wkl.[2] s. (Umea University Medical Dissertations, ISSN 0346-6612 ; new ser. nr 135)