C++ :: Assigning Reference Variable To Another Of Same Type

What is wrong with assigning a reference variable to another reference variable of the same type? I guess I have not understood references very well.

1- In below code, the initialization list gets error because agent "object reference variable" cannot be initialized with a reference variable of the same type.

Code:
class Intention {
public:
Intention(Agent& agent,int Id, string name);

[Code] ....

In other places I have the same problem. In below code the assignment gets error (no overloaded function for assigning a reference to another reference?)

Code:
void Agent::setWorld(World& world) {
this->world = world;
}

//Note: this->world has a type of World&

2- In this other one, I want to assign reference of a vector member to a reference variable of the same type.

Code:
vector<Intention> intentions;
...
Intention& currentIntention = intentions[intentionsIterator]