1. Cho, I.: Graph Groupoids and Partial Isometries. ISBN: 978-3-8383-1397-9. LAP Publisher (2009)
2. Cho, I.: Fractals in Graphs. ISBN: 978-3-639-19447-0. VDM Publisher (2009)
3. Cho, I., Jorgensen, P.E.T.: C *-subalgebras generated by partial isometries. J. Math. Phys. doi: 10.1063/1.3056588 (2008)
4. Cho, I., Jorgensen, P.E.T.: Application of automata and graphs I. ACTA Appl. Math. doi: 10.1063/1.3141524 (2008)
5. Cho, I., Jorgensen, P.E.T.: C *-subalgebras generated by a single operator in B(H). J. Math. Phys. doi: 10.1007s/10440-009-9478-5 (2008)