1. Agagu OK, Ekweozor CM (1982) Source rock characteristics of Senonian shales in the Anambra Syncline. J Miner Geol 19(1):132–140
2. Aleke CG, Okogbue COB, Aghamelu OP, Nnaji NJ (2016) Hydrogeological potential and qualitative assessment of groundwater from the Ajali Sandstone at Ninth Mile area, southeastern Nigeria. Environ Earth Sci 75:290. https://doi.org/10.1007/s12665-015-4843-3
3. Amah JI, Okoyeh EI, Onwuka SO (2016) Statistical modeling of the hydrostratigraphy and hydraulics of the Cretaceous aquifers in Nsukka, North of the Anambra basin, Southeast Nigeria. Pelagia J Appl Sci Res 7(4):32–41
4. American Public Health Association (APHA) (1995) Standard Methods for the Examination of Water and Wastewater, 19th edn. American Public Health Association Inc., New York
5. American Public Health Association (APHA) (2012) Standards methods for the examination of water and wastewater, 22nd edn, American Public Health Association (APHA), American Water Works Association (AWWA) and Water Environment Federation (WEF), New York, p 1360