TY  - GEN
TI  - Lecture notes
SN  - 1476-4687
PY  - 2013///1227
KW  - Physics
KW  - economics
KW  - Textbooks as Topic
KW  - standards
KW  - Universities
N1  - Publication Type: Editorial
UR  - https://doi.org/10.1038/504008a
ER  -