و آر ایل:https://www.researchgate.net/profile/Claiton-Scherer/publication/229094195/figure/download/fig3/AS:317241938726914@1452647780440/A-Optical-photomicrograph-of-heterogeneous-sedimentary-rocks-with-disseminated-iron.png
و آر ایل:https://www.researchgate.net/figure/A-Optical-photomicrograph-of-heterogeneous-sedimentary-rocks-with-disseminated-iron_fig3_229094195
