[R] selection bias adjustment via propensity score

[Bunny, lautloscrew.com]

Hi all,

i am wondering if there´s any other method to adjust for selection  
related bias of estimates except propensity scoring and heckit / mills  
ratio approach? i also read documentation of Match and twang package  
so far, so i don´t speak of any ATE / ATT related methods,  
respectively any methods that match or stratify... Is there something  
else ?

thx in advance