Reference:

Krista Lagus, Samuel Kaski, and Teuvo Kohonen. Mining massive document collections by the WEBSOM method. Information Sciences, 163(1–3):135–156, 2004.

Suggested BibTeX entry:

@article{Lagus04.ins,
    author = {Krista Lagus and Samuel Kaski and Teuvo Kohonen},
    journal = {Information Sciences},
    number = {1--3},
    pages = {135--156},
    title = {Mining massive document collections by the {WEBSOM} method},
    volume = {163},
    year = {2004},
}