@article{Azevedo1993, 
     author = "Azevedo, Jos\'{e}Augusto and {Santos Costa}, Maria Em\'{\i}lia O. and {Silvestre Madeira}, Joaquim Jo\~{a}o E.R. and {Vieira Martins}, Ernesto Q.", 
     doi = "10.1016/0377-2217(93)90095-5", 
     issn = "03772217", 
     journal = "European Journal of Operational Research", 
     keyword = "labelling algorithms,network,principle of optimality,shortest path", 
     link = "http://linkinghub.elsevier.com/retrieve/pii/0377221793900955", 
     month = "aug", 
     number = "1", 
     pages = "97--106", 
     title = "An algorithm for the ranking of shortest paths", 
     uri = "http://linkinghub.elsevier.com/retrieve/pii/0377221793900955", 
     volume = "69", 
     year = "1993", 
}

Problems: 56