Books:

• Laboratory Manual at Upper Primary Stage Science Class VI – VIII (Page no - 170) 
• NCERT Science Textbook - Class VII (Chapter 9: Soil) 

Websites:

• https://ncert.nic.in/pdf/school-kit/LMUPS_Science.pdf (Page no - 184)
• https://www.fao.org/3/r4082e/r4082e03.htm 
• https://www.usgs.gov/special-topics/water-science-school/science/infiltration-and-water-cycle 
• http://soilquality.org/indicators/infiltration.html