Find guidelines for your international mail on the Universal Postal Union website:

Here is a few examples to selected countries (mail sent from Norway):

Mr. H. C. Andersen
Eventyrvejen 1
DK-5000 ODENSE
DANMARK

Mr. Jón Jónsson
Einimel 80
IS-107 REYKJAVIK
ISLAND

Mrs. Inger Lilja
Vasavägen 3
SE-582 20 LINKÖPING
SVERIGE

Mr. A. H. van Doorn
P.O.Box 1992
2130 GC HOOFDORP
NEDERLAND

Mr. Walter C. Brown
312 Glasgow Row
LONDON WC1B 4BH
STORBRITANNIA

Herrn Erich Müller
Hilpertst. 31
DE-64296 DARMSTADT
TYSKLAND

Mrs. Lucy Stevens
2701, promenade Riverside
OTTAWA ON K1A 0B1
CANADA

John J. Bursenos
12603 Denmark Drive,
Apt.556
HERNDON, VA 22071-
9945
USA

Mr. P. G. Short
GPO Box 1777Q
MELBOURNE VIC
3001
AUSTRALIA

Mr. Lee
3-3 Otemachi 2 Chome,
Chiyoda-ku
TOKYO 100-31
JAPAN