@incollection{LotufoMM00,
 author    = "R. A. Lotufo and A. X. Falc{\~{a}}o",
 booktitle = "Mathematical Morphology and its Applications to Image and Signal Processing",
 title     = "The ordered queue and the optimality of the watershed approaches",
 publisher = "Kluwer",
 volume    = "18",
 month     = "Jun",
 pages     = "341--350",
 year      = "2000"
}