Westheimer G, Wehrhahn C (1997). “Real and virtual borders in the Poggendorff illusion”. 《Perception》 26 (12): 1495–501. doi:10.1068/p261495. PMID9616477.
Day, R.H. (1973). “The oblique line illusion: The poggendorff effect without parallels”. 《The Quarterly Journal of Experimental Psychology》 25 (4): 535–541. doi:10.1080/14640747308400375. PMID4767535.
Westheimer G, Wehrhahn C (1997). “Real and virtual borders in the Poggendorff illusion”. 《Perception》 26 (12): 1495–501. doi:10.1068/p261495. PMID9616477.
Day, R.H. (1973). “The oblique line illusion: The poggendorff effect without parallels”. 《The Quarterly Journal of Experimental Psychology》 25 (4): 535–541. doi:10.1080/14640747308400375. PMID4767535.