@article{Martins1984, 
     author = "Martins, Ernesto de Queir\'{o}s Vieira", 
     doi = "10.1016/0377-2217(84)90269-8", 
     issn = "01716468", 
     journal = "European Journal of Operational Research", 
     link = "http://www.sciencedirect.com/science/article/pii/0377221784902698", 
     number = "1", 
     pages = "123--130", 
     title = "An algorithm for ranking paths that may contain cycles", 
     uri = "http://www.sciencedirect.com/science/article/pii/0377221784902698", 
     volume = "18", 
     year = "1984", 
}

Problems: 80