Looking for co-authors interested in using the various ranking systems (Gravelius, Horton, Strahler, Botanical, Horsfield, Tokunaga, etc.) applicable rivers catchement (Case study Jijila river, Dogrogea, Romania). Article highlights the disadvantages and advantages of each model. I want to implement a model (with application in geography, biology, neurology) to comprise aspects of the existing ranking models. I'm open to ideas from all those interested.