||Mizunami M. Functional diversity of neural organization in insect ocellar systems. Vision Res. 1995 Feb35(4):443-52 DOI: 10.1016/0042-6989(94)00192-o p.444 right column 3rd paragraphPubMed ID7900285
||Weber G, Renner M. The ocellus of the cockroach, Periplaneta americana (Blattariae): receptory area. Cell Tissue Res. 1976 May 6 168(2):209-22 DOI: 10.1007/bf00215878PubMed ID1268935
||Primary source abstract: "The ocelli of Periplaneta americana were studied by light and electron microscopy."
||P.444 right column 3rd paragraph: "The number of photoreceptors contained in the ocellar retina is about 10,000 (primary source), the largest number among insects, and the volume of the rhabdom is very large."