SortedMerge() using recursion

[anderton7x]

I have come upon a code, which entails recurcion, while I was studying linked lists. I don't know if the guy wrote the code the right way it's supposed to be. It handles the first case scenario --if one of the lists to be merged is is empty-- yet in further passes I don't see a condition to stop the recursion properly.
The condition that will stop the recurcion felt awkward to me and I thought I could ameliorate the code and come up with a better one. I don't know though if mine is perfectly correct.

Below this code I tried to improve on it in my own fashion, wrong however it might be.

struct node *SortedMerge3(struct node *a, struct node *b)
{
     struct node *result;

     if(a == NULL){                        
	  return b;
     }
     else if(b == NULL){
	  return a;
     }
	  

     if(a->data <= b->data){
	  result = a;
	  result->next = SortedMerge3(a->next, b);
     }

     else{
	  result = b;
	  result->next = SortedMerge3(b->next, a);


	  return(result);
     }


}



struct node *SortedMerge3(struct node *a, struct node *b)
{
     struct node *result;
     struct node dummy;
     result = &dummyl;
     dummy->next = NULL;


     if(a == NULL){
	  result->next = b;
	  result = result->next;
	  return result;
     }
     else if(b == NULL){
	  result->next = a;
	  result = result->next;
	  return result;
     }
	  

     if(a->data <= b->data){
	  result = a;
	  result->next = SortedMerge3(a->next, b);
     }

     else{
	  result = b;
	  result->next = SortedMerge3(b->next, a);
    }
}

[dwks]

So which one was the original version? The first one?

[edit]What's that dummy stuff for?[/edit]