Baltic and Slavic and Indo-European 

The vast majority of Indo-Europeanists accept Baltic as a valid single clade within Indo-European (see the various stammbaum offered in all the modern introductory texts on Indo-EuropeanFortson, Clackson, etc.).  The notion that there was no Baltic clade is not supported within the mainstream Indo-European literature.  The whole section "Modern interpretation" is not based on modern, accepted Indo-European scholarship, but is a WP:FRINGE position from the 1960s.  It is not accepted in the 21st century by the vast majority of Indo-Europeanists.  Fortson (2010, Indo-European Language and Culture), Mallory & Adams (2006, The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World), Szemerényi (1990, Introduction to Indo-European Linguistics), Beekes (1995, Comparative Indo-European Linguistics), Schmalsteig (1998, "The Baltic Languages," The Indo-European Languages, ed. Ramat & Ramat), Clackson (2007, Indo-European Linguistics), Baldi (1983, An Introduction to the Indo-European Languages), etc. all support Baltic as a clade.  This is the mainstream position and the "Baltic is not a clade" is a minority view and to give it an entire section violates WP:UNDUE.