Dijkstra, E.W. (1959). A note on two problems in connexion with graphs. Numer. Math., 1, 269-71.
Dreyfus, S.E. (1969). An appraisal of some shortest-path algorithms. Operations Res., 17, 395-412.
Edmonds, J. (1965). Paths, trees and flowers. Canad. J. Math., 17, 449-67