Reference
Britannica Dictionary Question - Age designation by decade?
Book Collections Online (https://onlinebooks.library.upenn.edu/)
College Board SAT and SAT Subject Tests (https://research.collegeboard.org/programs/sat)
Complete English Grammar Rules (.pdf)
Datausa.io has extensive Data Research; search universities (UMCP - datausa.io)
Stanford Encyclopedia of Philosophy (Link)
US Census Quickfacts (Massachusetts)
- Sample (Richmond, VA)
Vocabulary list (6000 words)