Historical clue formulations

• Cartoonist whom John Steinbeck said "may very possibly be the best writer in the world today" — 2015-12-24
• Creator of Stupefyin' Jones — 2015-06-14
• Creator of Fearless Fosdick — 2013-10-16
• Creator of Stupefyin' Jones — 2009-06-06
• Mammy Yokum's creator — 2004-11-14
• Dogpatch's creator — 2003-10-15
• Cartoonist who helped start an amusement park in Arkansas — 2002-09-06
• Mammy Yokum's creator — 2002-05-05