Need help sorting a linked list.

is this a singly linked list or a doubly linked list :

typedef struct lListAirPdata { airPdata *curAirPdataP; //Pointer to the Airport Data struct lListAirPdata *nextAirPdataList; // pointer to next } lListAirPdata;

also, what would be the best way to alphabetically sort this list. (will have strings containing both letters and numbers in any order.) im assuming it will be ordered numerically and then alphabetically