need help sexing bombinas.

[flamel2007]

can u guys please help. ive tried to learn several times how to sex bombinas but i can never guess right.... i have this 4 bombinas and i want to breed then, but im not sure if they are male or female. there are 3 photos of each.

frog number 1:



frog number 2:


frog number 3:


frog number 4:




so. each one is male or female? please i need ur help guys!!!!