The modulus of a weakly compact operator

Abramovič, Y.: Some theorems on normed lattices. Vestnik Leningrad. Univ. Mat. Mekh. Astronom.13, 5–11 (1971) (Engl. Transl: Vestnik Leningrad Univ. Math. vol. 4 (1977))

Aliprantis, C.D., Burkinshaw, O.: Positive operators. New York-San Francisco-London: Academic Press 1985

Cartwright, D.I., Lotz, H.P.: Some characterizations ofAM-andAL-spaces. Math. Z.142, 97–103 (1975)

Diestel, J., Uhl, J.J., Jr.: Vector measures. Math. Surveys, A.M.S., Providence, 1977

Luxemburg, W.A.J., Zaanen, A.C.: Notes on Banach function spaces, II and III. Indagationes Math.25, 148–153 and 239–250 (1963)

Schaefer, H.H.: Banach lattices and positive operators. Berlin-Heidelberg-New York: Springer 1974