A Telemedical Approach to the Screening of Diabetic Retinopathy: Digital Fundus Photography. - Liesenfeld,B.; Kohner,E.; Piehlmeier,W.; Kluthe,S.; Aldington,S.; Porta,M.; Bek,T.; Obermaier,M.; Mayer,H.; Mann,G.; Holle,R.; Hepp,. (Diabetes Care, 2000)