Citation and Formating
OWL Purdue: https://owl.english.purdue.edu/
Citation Machine: http://www.citationmachine.net/
Easy Bib: http://www.easybib.com/
Writing and Style Tips
Introductions: https://owl.english.purdue.edu/engagement/2/2/58/
Other
Editing and Revision: https://www.paperrater.com/