Guide to multiple styles:

https://library.usciences.edu/help/how-to-write-a-reference.asp
https://owl.english.purdue.edu/owl/section/2/
http://www.bibme.org/citation-guide/

APA style Guide:

http://www.bibme.org/citation-guide/apa/
http://owl.english.purdue.edu/owl/resource/560/10/
http://sites.umuc.edu/library/libhow/apa_examples.cfm
http://employees.csbsju.edu/proske/nursing/apa.htm

ACS style:

http://library.williams.edu/citing/styles/acs.php
https://library.usciences.edu/help/citation-acs.asp

Links to help with the understanding of statistics:

http://www.stats.gla.ac.uk/steps/glossary/
http://wise.cgu.edu

http://researchbasics.education.uconn.edu
http://vassarstats.net
http://onlinestatbook.com/stat_sim/

Free stat software:
http://statpages.info/javasta2.html
https://www.medcalc.org

Links to specific statistics:

McNemar's test:
https://graphpad.com/quickcalcs/mcNemar1/

http://vassarstats.net/propcorr.html

Kruskal-Wallis Test:
http://vassarstats.net/textbook/ch14a.html
http://www.itl.nist.gov/div898/software/dataplot/refman1/auxillar/kruskwal.htm

Significance of the difference between two correlations:
http://www.danielsoper.com/statcalc/calculator.aspx?id=104
https://www.psychometrica.de/correlation.html
http://comparingcorrelations.org

Cronbach's alpha:
https://en.wikipedia.org/wiki/Cronbach%27s_alpha