HERSCHEL, John Frederick William. Observations of Nebulæ and Clusters of Stars, Made at Slough, with a Twenty-Feet Reflector, between the Years 1825 and 1833. Philosophical Transactions of the Royal Society of London. 1833, roč. 123, s. 359–505. doi:10.1098/rstl.1833.0021. (anglicky)
Revised NGC Data for NGC 44. spider.seds.org [online]. Students for the Exploration and Development of Space [cit. 2026-08-29]. Dostupné online. (anglicky)