Books

• Laboratory Manual at Upper Primary Stage Science Class VI – VIII (Activity 39) 
• NCERT Science Textbook - Class VIII  

  Websites

• https://ncert.nic.in/pdf/publication/sciencelaboratorymanuals/classVItoVIII/science/fhelm205.pdf (Page Number :14 , Activity :39)
• https://www.ehow.com/info_8003522_uses-dropper.html