SQL: Select all rows that are in range of 2 kilometres

Assuming I have the following PostgresSQL table locations name/longitude/latitude:

name |        longitude |        latitude 
----------------------------------------- 
A    |   14.02023923239 | 13.020239232393
B    |   23.29328403231 | 20.203923847782
C    |    8.02392784729 | 50.302398462732
D    |   28.23828482848 | 29.845102045853
E    |   32.20328328849 | 39.923828328782

How can I select the rows that are in a radius of (for example) 10 kilometers from a starting point longitude 13.99999999999 and latitude 12.99999999999?

I accept any answer that gives me a concrete SQL statement.

Answer

Thanks guys. I found this stored procedure on some website (forgot the link). It works really well implementing the Haversine formula:

CREATE OR REPLACE FUNCTION calculate_distance(lat1 float, lon1 float, lat2 float, lon2 float, units varchar)
RETURNS float AS $dist$
    DECLARE
        dist float = 0;
        radlat1 float;
        radlat2 float;
        theta float;
        radtheta float;
    BEGIN
        IF lat1 = lat2 OR lon1 = lon2
            THEN RETURN dist;
        ELSE
            radlat1 = pi() * lat1 / 180;
            radlat2 = pi() * lat2 / 180;
            theta = lon1 - lon2;
            radtheta = pi() * theta / 180;
            dist = sin(radlat1) * sin(radlat2) + cos(radlat1) * cos(radlat2) * cos(radtheta);

            IF dist > 1 THEN dist = 1; END IF;

            dist = acos(dist);
            dist = dist * 180 / pi();
            dist = dist * 60 * 1.1515;

            IF units = 'K' THEN dist = dist * 1.609344; END IF;
            IF units = 'N' THEN dist = dist * 0.8684; END IF;

            RETURN dist;
        END IF;
    END;
$dist$ LANGUAGE plpgsql;

With that stored procedure, I was able to build a SQL select:

select 
    *
from 
    locations
where
    calculate_distance(latitude, longitude, 13.99999999999, 12.99999999999, 'K') < 2