by Kim, Soo-Hwan, Kim, Yang-Kok
Published in Kyungpook mathematical journal (2012)

by Kim, Soo-Hwan, Kim, Yang-Kok
Published in Journal of the Korean Mathematical Society (2009)

by Kim, Yang-Kok
Published in Journal of the Korean Mathematical Society (1997)

by Kim, Goan-Su, Kim, Yang-Kok, Vesnin, Andrei
Published in Journal of the Korean Mathematical Society (1998)

by Kim, Soo-Hwan, Kim, Yang-Kok
Published in Kyungpook mathematical journal (01.06.2012)

by Kim, Soo-Hwan, Kim, Yang-Kok
Published in Journal of the Korean Mathematical Society (01.11.2009)