Analysis of information sources in references of the Wikipedia article "Steppe" in English language version.
There are many definitions of steppes. For example, Allan (1946) provides fifty-four definitions of this term. Stamp and Clark (1979) define steppes as 'mid-latitude areas dominated by herbaceous vegetation and termed locally steppes, prairies, pampas, high veldts, downland, etc.'
[...] the critical era when innovative Proto-Indo-European dialects began to spread across the steppes.
