ElektrotehnikaHollmann, Roman1946 https://www.ester.ee/record=b1466040*est

Elektrotehnika. 1Hollmann, Roman1947 https://www.ester.ee/record=b1335230*est

Elektrotehnika. 2Hollmann, Roman1948 https://www.ester.ee/record=b1440868*est

Üldine elektrotehnikaEsop, Harri; Hellam, Hartvig; Hollmann, Roman; Kanasaar, Eduard; Kroon, Arnold-Konstantin; Plakk, Paul; Puusepp, Eugen; Riikoja, Helmut Erik1949 https://www.ester.ee/record=b1394972*est