During the period between 1582, when the first countries adopted the Gregorian calendar, and 1923, when the last European country adopted it, it was often necessary to indicate the date of some event in both the Julian calendar and in the Gregorian calendar, for example, "10/21 February 1750/51", where the dual year accounts for some countries already beginning their numbered year on 1 January while others were still using some other date. Even before 1582, the year sometimes had to be double dated because of the different beginnings of the year in various countries. Woolley, writing in his biography of John Dee (1527–1608/9), notes that immediately after 1582 English letter writers "customarily" used "two dates" on their letters, one OS and one NS.
When did the last country to adopt the Gregorian calendar start using it?
1923

Borders Books, started in Ann Arbor, was opened by brothers Tom and Louis Borders in 1971 with a stock of used books. The Borders chain was based in the city, as was its flagship store until it closed in September 2011. Domino's Pizza's headquarters is near Ann Arbor on Domino's Farms, a 271-acre (110 ha) Frank Lloyd Wright-inspired complex just northeast of the city. Another Ann Arbor-based company is Zingerman's Delicatessen, which serves sandwiches and has developed businesses under a variety of brand names. Zingerman's has grown into a family of companies which offers a variety of products (bake shop, mail order, creamery, coffee) and services (business education). Flint Ink Corp., another Ann Arbor-based company, was the world's largest privately held ink manufacturer until it was acquired by Stuttgart-based XSYS Print Solutions in October 2005. Avfuel, a global supplier of aviation fuels and services, is also headquartered in Ann Arbor. Aastrom Biosciences, a publicly traded company that develops stem cell treatments for cardiovascular diseases, is headquartered in Ann Arbor.
Avfuel, a global supplier of what services is headquartered in Ann Arbor?
aviation fuels

The Premier League is a corporation in which the 20 member clubs act as shareholders. Seasons run from August to May. Teams play 38 matches each (playing each team in the league twice, home and away), totalling 380 matches in the season. Most games are played on Saturday and Sunday afternoons; others during weekday evenings. It is currently sponsored by Barclays Bank and thus officially known as the Barclays Premier League and is colloquially known as the Premiership. Outside the UK it is commonly referred to as the English Premier League (EPL).
When do Premier League seasons run from?
August to May