SPSS References:

SPSS for Windows, Version 16.0. Chicago, SPSS Inc; 2007
SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc; 2008
PASW Statistics for Windows, Version 18.0. Chicago: SPSS Inc; 2009
IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp; 2010
IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp; 2011
IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp; 2012
IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp; 2013
IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp; 2015
IBM SPSS Statistics for Windows, Version 24.0. Armonk, NY: IBM Corp; 2016
IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp; 2017
IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp; 2019
IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp; 2020
IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY: IBM Corp; 2021

Stata References:

StataCorp. Version 12. College Station, TX: StataCorp LP; 2012
StataCorp. Version 13. College Station, TX: StataCorp LP; 2013
StataCorp. Version 14. College Station, TX: StataCorp LP; 2015
StataCorp. Version 15. College Station, TX: StataCorp LLC; 2017
StataCorp. Version 16. College Station, TX: StataCorp LLC; 2019
StataCorp. Version 17. College Station, TX: StataCorp LLC; 2021