The cyclic subgroup separability of certain HNN extensions. Wong, P.C.; Wong, K.B. — 2006 Bulletin of the Malaysian Mathematical Sciences Society. Second Series
Subgroup separability and conjugacy separability of certain HNN extensions. Wong, P.C.; Wong, K.B. — 2008 Bulletin of the Malaysian Mathematical Sciences Society. Second Series
Weak potency of fundamental groups of graphs of groups. Wong, P.C.; Tang, C.K.; Gan, H.W. — 2010 Bulletin of the Malaysian Mathematical Sciences Society. Second Series