1. Not Positive Definite Correlation Matrices in Exploratory Item Factor Analysis: Causes, Consequences and a Proposed Solution. Issue 1 (2nd January 2021) Authors: Lorenzo-Seva, Urbano; Ferrando, Pere J. Journal: Structural equation modeling Issue: Volume 28:Issue 1(2021) Page Start: 138 Record Type: Journal Article View Content: Available online (eLD content is only available in our Reading Rooms) ↗