1. Shen, Y.-b., Chen, P.-j. & Huang, D.-y. Age of fossil conchostracans from Daohugou of Ningcheng, Inner Mongolia [in Chinese with English abstract]. J. Stratigr. 27, 311–313 (2003)
2. Chen, W. et al. Isotope geochronology of the fossil-bearing beds in the Daohugou area, Ningcheng, Inner Mongolia [in Chinese]. Geol. Bull. Chin. 23, 1165–1169 (2004)
3. Zhang, J.-f. Discovery of Daohugou Biota (Pre-Jehol Biota) with a discussion on its geological age [in Chinese with English abstract]. J. Stratigr. 26, 173–177 (2002)
4. He, H.-y. et al. 40Ar/39Ar dating of ignimbrite from Inner Mongolia, northeastern China, indicates a post-Middle Jurassic age for the overlying Daohugou Bed. Geophys. Res. Lett. 31, L20609, doi:10.1029/2004GL020792. (2004)
5. Wang, X.-l. et al. Stratigraphy and age of the Dauhugou bed in Ningcheng, Inner Mongolia. Chin. Sci. Bull. 50, 2369–2376 (2005)