Excel calendar template - download free printable excel, Excel calendar templates monthly, yearly options holidays . numbers free monthly yearly calendar 2018 download . https://www.calendarlabs.com/excel-calendar/ Julian day - wikipedia, Julian gregorian calendar julian day number. algorithm richards convert julian day number, , date gregorian calendar. https://en.wikipedia.org/wiki/Julian_day Old style style dates - wikipedia, Old style (..) style (..) terms dates calendar convention time . https://en.wikipedia.org/wiki/Old_Style_and_New_Style_dates