Premonowati, P. et al. 2012. Allostratigraphy of Punung Paleoreef based on Lithofacies Distributions, Jlubang Area, Pacitan Region-East Java. Indonesian Journal on Geoscience. 7, 2 (Jun. 2012), 113–122. DOI:https://doi.org/10.17014/ijog.7.2.113 - 122.