Paper with 350,757 coin flips showing bias published in JASA
doi.org
doi.org
The main difference from the original version is that we now document a decrease in the same-side bias over time. Meaning the more people flip, the less biased they are. We guess that it's a practice effect -- they might be getting better at coin flipping over time.
(I'm the main author of the paper)
People flipping them however introduce bias due to the wobble of their tosses.