Merge pull request #63 from opengeospatial/chris-little-addIFCexample

Add IFC as example calendar

23-049/sections/08-temporal-regimes.adoc

@@ -71,7 +71,7 @@ In this regime, the use of the <<temporal_knowledge,Allen Operators>> (see <<fig
 
 Calendars are social constructs made by combining several clocks and their associated timescales.
 
-This Abstract Specification only addresses the internationally agreed Gregorian calendar. <<calendrical,Calendrical Calculations>> by Nachum Dershowitz and Edward M. Reingold provides overwhelming detail for conversion to numerous other calendars that have developed around the world and over the millennia and to meet the various social needs of communities, whether agricultural, religious or other. The reference is comprehensive but not exhaustive, as there are calendars that have been omitted.
+This Abstract Specification only addresses the internationally agreed Gregorian calendar. <<calendrical,Calendrical Calculations>> by Nachum Dershowitz and Edward M. Reingold provides overwhelming detail for conversion to numerous other calendars that have developed around the world and over the millennia and to meet the various social needs of communities, whether agricultural, religious or other. The reference is comprehensive but not exhaustive, as there are calendars that have been omitted. Wikipedia also has a comprehensive <<calendarlist,list of calendars>>.
 
 A Calendar is a Temporal Reference System, but it is not a Temporal Coordinate Reference System nor an Ordinal Temporal Reference System.
 

23-049/sections/09-attributes.adoc

@@ -113,6 +113,9 @@ The West African Yoruba traditional calendar is a solar calendar with months, bu
 [example]
 Teams controlling remote vehicles on Mars use a solar calendar, with Martian years and Martian days (called sols). Months are not used because there are two moons, with different, rather short, orbital periods.
 
+[example]
+The <<ifc,International Fixed Calendar>> was a solar calendar with 13 months of 28 days, with an extra day at the year's end after the thirteenth month and leap days inserted at the end of the sixth month. Months all started on the same day of the week, Sunday, and ended on a Saturday. The year-end day and leap days are not part of any week. The IFC was considered for global introduction by the League of Nations but finally rejected in 1937, though it formed the basis for some financial accounting systems for many years. 
+
 === Discrete and Continuous Time Scales
 
 A <<clock_section,clock>> may be a regular, repeating, physical event, or 'tick', that can be counted. The sequence of tick counts form a discrete (counted) <<timescale_section,timescale>>.

23-049/sections/annex-bibliography.adoc

@@ -18,6 +18,14 @@ Cambridge University Press. 2018.
 ISBN-13: 978-1107683167.
 http://emr.cs.iit.edu/home/reingold/calendar-book/third-edition [last accessed 2023-01]
 
+* [[[calendarlist,List of Calendars]]]
+Wikipedia.
+_List of Calendars_. https://en.wikipedia.org/wiki/List_of_calendars [last accessed 2023-12]
+
+* [[[ifc,International Fixed Calendar]]]
+Wikipedia.
+_International Fixed Calendar_. https://en.wikipedia.org/wiki/International_Fixed_Calendar [last accessed 2023-12]
+
 * [[[history_timekeeping,A Brief History of Timekeeping]]]
 Chad Orzell.
 _A Brief History of Timekeeping_.