[C++] Erreur link polymorphisme

// a.h

template <typename T>
struct A
{
    virtual ~A();
    virtual void print( T const & ) = 0;
};

// a.cpp

#include "a.h"

template <typename T>
A<T>::~A() { }

// b.h

#include "a.h"

struct Bint
    : public A<int>
{
    void print( int const & );
        // ~Bint();
};

// b.cpp

#include "b.h"

#include <iostream>

void Bint::print( int const & i )
{
    std::cout << i << std::endl;
}

//Bint::~Bint() { }

// main.cpp

#include "b.h"

int main( int argc, char ** argv )
{
    Bint b;
    b.print( 1 );

    return 0;
}

Error   LNK2019 unresolved external symbol "public: virtual __thiscall A<int>::~A<int>(void)" (??1?$A@H@@UAE@XZ) referenced in function "public: virtual __thiscall Bint::~Bint(void)" (??1Bint@@UAE@XZ)

Error   LNK2001 unresolved external symbol "public: virtual __thiscall A<int>::~A<int>(void)" (??1?$A@H@@UAE@XZ)