Chapter 2 of the same authored book. Book publication is April 2018; no online chapter revision date is inferred.
Cited passages: Watrous, The Theory of Quantum Information, §2.1.2, printed pp. 62–64, Definition 2.5 and pure states; §2.3, Definition 2.34, measurement probabilities.
Chapter 1 of the authored book published by Cambridge University Press in April 2018. The online chapter does not establish a manuscript revision date.
Cited passages: Watrous, The Theory of Quantum Information, §1.1.2, printed pp. 17–18, equations (1.94)–(1.97), Hermitian, positive semidefinite and density operators; finite-dimensional setting.