Tetsuo Kamina Tomoyuki Aotani Atsushi Igarashi On-Demand Layer Activation for Type-Safe Deactivation. 4:1-4:7 2014 COP@ECOOP https://doi.org/10.1145/2637066.2637070 conf/ecoop/2014cop db/conf/ecoop/cop2014.html#KaminaAI14