@article {De Vries:1974:0015-749X:129,
	author = "De Vries, P. G.",
	title = "Multi-Stage Line Intersect Sampling",
	journal = "Forest Science",
	volume = "20",
	number = "2",
	year = "1974",
	abstract = "With the use of a generalisation of the theory of single-stage line intersect sampling, estimators for population total per unit area and variance are derived for the case of line intersect three-stage sampling. In this case line intersect sampling is followed by two further stages of sampling: a sample from the intersecting first-order elements and a sample from the second-order elements that constitute the latter. Estimators for two types of two-stage sampling follow as special cases. The techniques developed may reduce costs or make sampling feasible in cases where single-stage line intersect sampling is impractical. Forest Sci. 20:129-133.",
	pages = "129-133",
	url = "http://www.ingentaconnect.com/content/saf/fs/1974/00000020/00000002/art00006",
	keyword = "Sampling methods, forest inventory"
}