What are the differences between extreme programming and agile methodology?

What are the differences between extreme programming and agile methodology? Paper details: 1 page. AT LEAST 3 references cited in APA. References cannot be books or websites. Journal Articles ONLY. Assignment is submitted through SafeAssign for plagiarism check. References: Please do NOT just copy and paste the "APA" reference from what the search engine program produces. 90% of the time they will be in the wrong format because they are not using a transformation algorithm, just placeholders. Here are some examples: Smith, J. (2012) The article title, Name of Journal, 24(11) Name: Last names have first letter only capitalized. First names are never used, only the first initial in upper-case followed by a period. Commas between names if multiple authors. Year: in parentheses. If more than one article by the same author in a given year, use a,b,c,etc. for each successive one. Title: ONLY the first letter of the first word is capitalized. The only exceptions are for acronyms or proper names. Journal name: In italics. Capitalize the first letter of first word and all major words. Volume: In italics and JUST the number. Number or Issue: In parentheses, just the number, and next to the volume number. Note that page numbers are optional and if used are in the form p.123