HEHNE, D. S. Polysegmental lumbar osteotomies and transpedicled fixation for correction of long-curved kyphotic deformities in ankylosing spondylitis ; Report on 177 cases. Clin. Orthop. 1990, 258, 49-55
HERMENS, D. J. Exacerbation of ulcerative colitis. Gastroenterology. 1991, 101, 254-262