Reference:

Samuel Kaski, Timo Honkela, Krista Lagus, and Teuvo Kohonen. WEBSOM—self-organizing maps of document collections. Neurocomputing, 21:101–117, 1998.

Suggested BibTeX entry:

@article{Kaski98,
    author = {Samuel Kaski and Timo Honkela and Krista Lagus and Teuvo Kohonen},
    journal = {Neurocomputing},
    pages = {101-117},
    title = {{WEBSOM}---Self-Organizing Maps of Document Collections},
    volume = {21},
    year = {1998},
}