Goldberg, L. R. "International Personality Item Pool: A scientific collaboratory for the development of advanced measures of personality and other individual differences". Archived from the original on 2014-05-24. Retrieved 2014-05-26. https://web.archive.org/web/20140524063221/http://ipip.ori.org/ipip/
Lewis R. Goldberg; John A. Johnson; Herbert W. Eber; Robert Hogan; Michael C. Ashton; C. Robert Cloninger; Harrison G. Gough. "The international personality item pool and the future of public-domain personality measures". http://ipip.ori.org/Goldberg_etal_2006_IPIP_JRP.pdf
The 3,329 IPIP Items in Alphabetical Order (plus their Survey and Item Number*) [1] https://ipip.ori.org/alphabeticalitemlist.htm
"Single-Construct IPIP Scales". ipip.ori.org. https://ipip.ori.org/newSingleConstructs.htm
"Multi-Construct IPIP Inventories". ipip.ori.org. Retrieved 6 March 2019. https://ipip.ori.org/newMultipleconstructs.htm
"16PF Comparison Table". Retrieved 6 March 2019. https://ipip.ori.org/new16PFTable.htm
"Big-Five Factor Markers". Retrieved 6 March 2019. https://ipip.ori.org/newBigFive5broadKey.htm
"Administering IPIP Measures, with a 50-item Sample Questionnaire". Retrieved 6 March 2019. https://ipip.ori.org/New_IPIP-50-item-scale.htm
[Rationale for the IPIP https://web.archive.org/web/20050313001046/http://ipip.ori.org/newRationale.htm] https://web.archive.org/web/20050313001046/http://ipip.ori.org/newRationale.htm
[Rationale for the IPIP https://web.archive.org/web/20050313001046/http://ipip.ori.org/newRationale.htm] https://web.archive.org/web/20050313001046/http://ipip.ori.org/newRationale.htm
Johnson, John A. "IPIP NEO-PI, Introductory Information". Retrieved 6 March 2019. http://personal.psu.edu/~j5j/IPIP/
Johnson, John A. (August 2014). "Measuring thirty facets of the Five Factor Model with a 120-item public domain inventory: Development of the IPIP-NEO-120". Journal of Research in Personality. 51: 78–89. doi:10.1016/j.jrp.2014.05.003. /wiki/Doi_(identifier)
Lewis R. Goldberg (1999). Mervielde, I.; Deary, I.; De Fruyt, F.; Ostendorf, F. (eds.). "A broad-bandwidth, public domain, personality inventory measuring the lower-level facets of several five-factor models" (PDF). Personality Psychology in Europe. 7: 7–28. https://ipip.ori.org/A%20broad-bandwidth%20inventory.pdf
Goldberg, Lewis R. (1992). "The development of markers for the Big-Five factor structure". Psychological Assessment. 4 (1): 26–42. doi:10.1037/1040-3590.4.1.26. /wiki/Doi_(identifier)
"Take a personality test - Open Source Psychometrics Project". Retrieved 6 March 2019. https://openpsychometrics.org/