Hypothetical superparamagnetic magnetometer in a pigeon’s upper beak probably does not workPetr Jandačka, Petr Alexa, Jaromír Pištora and Jana TrojkováEur. Phys. J. E, 36 4 (2013) 40DOI: https://doi.org/10.1140/epje/i2013-13040-1