Sharma, A., Sharma, V.K., Parwar, R., Joshi, N., Prakash, M., Nirmala, M. and Verma, V. 2006. Morphological details of new irregular Echinoid fossil from Zirabad, India. Environment Conservation Journal. 7, 3 (Dec. 2006), 107–111. DOI:https://doi.org/10.36953/ECJ.2006.070317.