Hemlock B Bootsalotta

The point with Wikipedia is that if the article is properly sourced it has the external references that allow a reader to validate its claims. The Gen-X articles have that.

As far as the English language goes, an academic is still just some guy. Everybody is just some guy. A words definition is only ever the consensus opinion of its meaning at a given time.

So, if you don't like Wikipedia, here's what the four major English dictionaries - Oxford, Collins, Merriam-Webster and American Heritage - say. None of them include a definition of early 60's, so using that definition is going to confuse most people you talk to. It's true that there doesn't seem to be a consensus as to exactly when it started and finished, but it definitely includes the period '65 - '75.

Oxford Dictionaries free definition:
the generation born after that of the baby boomers (roughly from the early 1960s to mid 1970s), typically perceived to be disaffected and directionless

Merriam-Webster
the group of people in the U.S. who were born during the late 1960s and the 1970s

American Heritage Dictionary
The generation following the post-World War II baby boom, especially people born in the United States and Canada from the early 1960s to the late 1970s.

Collins English Dictionary
members of the generation of people born between the mid-1960s and the mid-1970s who are highly educated and underemployed, reject consumer culture, and have little hope for the future