Gaya APA
Heuff, J., Iammeling, B. (1990).
Groningen at 950: the once and future city .
Netherlands:
Wolters-Noord BV Groningen.
Gaya MLA
Heuff, Jan., Iammeling, Bart.
"Groningen at 950: the once and future city".
Netherlands:
Wolters-Noord BV Groningen,
1990.
Text.