A description and the use of an event-generator code for two-photon processes at e+e- colliders, TREPS, are presented. This program uses an equivalent photon approximation in which the virtuality of photons is taken into account. It is applicable to
various processes by specifying a combination of final-state particles and the angular distributions among them. A comparison of the results with those from other programs is also given.
The X(3872) and Z(4430) are candidates of tetraquark state with a ccbar pair. We present results from Belle recently updated for the mass, branching fractions etc. in different production/decay processes of the X(3872). Results from a Dalitz analysis
for B --> Z(4430) K --> psi pi^+- K are also presented.
