The 'G' in 'GMT'

The "G" in "GMT stands for Goodman, the newspaper editor/explorer who first cracked the calendar glyphs. The quotes of "17  Mayan calendars" comes from a calculation done in the same way as if you said "we ourselves have 12 calendars ... solar calendar, lunar calendar, days, weeks, months, seasons, 365-day years, 366-day leap years, decades, centuries, millennia"... in other words, they include cycles as well as whole calendars. For those who want to know more about Goodman and read a ground-breaking illustrated piece of calendar research by an independent researcher, but which has been praised by 3 academic Mayanists, see this essay: http://independent.academia.edu/GeoffStray