This is what we found on Wikipedia regarding the Dead On A Sunday:

Sunday (Latin: dies solis meaning "day of the sun") is the day of the week between Saturday and Monday. Sunday is a day of rest in most Western countries and a part of the weekend. In some Arab countries, Sunday is a weekday.

For most Christians, Sunday is observed as a day of worship and rest, holding it as the Lord's Day and the day of Christ's resurrection; in the United States, Canada, Japan, as well as in parts of South America, Sunday is the first day of the week. According to the Islamic calendar, Hebrew calendar and traditional calendars (including Christian calendars) Sunday is the first day of the week; Quaker Christians call Sunday the "first day" in accordance with their testimony of simplicity. The International Organization for Standardization standard ISO 8601 puts Sunday as the seventh day of the week.