Aaltio, Erkki <br/><br/>
Investigations on the mode of combination of lignin in wood, with special reference to aspen (populus tremula) wood 

 - Helsinki :   Suomalainen Tiedeakatemia,   1958. 
 - 58 p. ;   21 cm. 
 - Annales Academiae Scientiarum Fennicae .