Hamel, Dennis R, Robert D Oakes, and United States. Forest Service. Northern Region. State & Private Forestry. Status of Mountain Pine Beetle Infestations In Second-growth Ponderosa Pine Stands, Little Belt and Big Snowy Mountains, Lewis & Clark National Forest, Montana, 1976. : Missoula, MT. : Forest Insect & Disease Management, USDA, Forest Service, Northern Region, State & Private Forestry, 1977.