Read this:
http://www.britannica.com/eb/article-74567/Indo-European-
languages It finally proofs that Grundriß der vergleichenden Grammatik
der indogermanischen Sprachen and Indogermanisches etymologisches
Wörterbuch are the _latest completed full treatment of the whole PIE
family_ and the _most recent etymological dictionary of the whole
PIE family_.