A minimal pair is two words that differ in only one sound.
Kensinger, Kenneth M. 1963. "The phonological hierarchy of Cashinahua." Elson 1963. Norman, OK: University of Oklahoma Press.
Burquest, Donald A., and David L. Payne. 1993.Phonological analysis: A functional approach. Dallas, TX: Summer Institute of Linguistics. (Burquest 1998.)