Data abstractions provide the same benefits as procedures, but for data. Recall that the main idea is to separate what an abstraction is from how it is implemented so that implementations of the same abstraction can be substituted freely.

— Barbara Liskov, Keynote speech at OOPSLA 87 (1987)

Source: https://devopedia.org/solid-design-principles#milestones

From her OOPSLA 87 keynote; the citation links it to the Liskov Substitution Principle.

Topics: software design