1. Aleksandrov, P. S.: Introduction into set theory and general topology, Russian, With the collaboration of V. I. Zaĭcev and V. V. Fedorčuk, Izdat. “Nauka”, Moscow, 367 (1977)
2. Aliprantis, C.D., Burkinshaw, O.: Positive operators, Reprint of the 1985 original. Springer, Dordrecht, xx+376 (2006)
3. Banakh, T., Kucharski, A., Martynenko, M.: A spectral characterization of skeletal maps. Cent. Eur. J. Math. 11(1), 161–169 (2013)
4. Beckenstein, E., Narici, L.: Topological vector spaces, Pure and Applied Mathematics (Boca Raton), 296, 2. CRC Press, Boca Raton, FL, xviii+610 (2011)
5. Blokh, A., Oversteegen, L., Tymchatyn, E.D.: On almost one-to-one maps. Trans. Am. Math. Soc. 358(11), 5003–5014 (2006)