References

Parham JF, Donoghue PCJ, Bell CJ, Calway TD, Head JJ, Holroyd PA, Inoue JG, Irmis RB, Joyce WG, Ksepka DT, et al. 2012. Best practices for justifying fossil calibrations. Systematic Biology 61: 346-359. http://dx.doi.org/10.1093/sysbio/syr107