Buck, C., D. (1949). A dictionary of selected synonyms in the principal Indo–European languages: a contribution to the history of ideas. Chicago: University of Chicago Press.
Matasović, Ranko. Etymological Dictionary of Proto-Celtic. Indo-European Etymological Dictionaries Online. Edited by Alexander Lubotsky. Brill. Brill Online: http://iedo.brillonline.nl.ludwig.lub.lu.se/dictionaries/content/proto-celtic/index.html
Griffiths, Bruce & Dafydd Glyn Jones. Geiriadur yr Academi, the Welsh Academy English-Welsh Dictionary Online. http://geiriaduracademi.org/?lang=en
Robert Farren, PIE culture words collection, 2017
Any ancestors and descendants of the selected element are shown in the graph, but siblings and cousins are not.
The element in question is marked in green.
When the etymological tree is displayed in hierarchical style, the nodes can be repositioned manually only within their level.
(Note that the node configuration is not saved in any way.)
The graph as a whole can be zoomed in on by scrolling and can be enlarged by dragging the right-lower corner.
Left-click on a node or edge to show additional information and links. In some browsers, the graph may be savable as an image when right-clicking on it.
This map shows the etymological links in a geographic context.