Ouden, P. den  1874-1964. <br/><br/>
Manual of cultivated conifers :  hardy in the cold and warm temperate zone / 
by P. Den Ouden, in collaboration with B. K. Boom. 
 - The Hague :  Martinus Nijhoff,  1978. 
 - 526 p. :  ill., plates ;  26 cm. 
<br/><br/><label>ISBN: </label>9024721482 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Conifers.<br/>Conifers--Varieties.