Merge pull request #86 from robinzyb/devel

fix typo in plot doc

docs/cube/README.md

@@ -72,7 +72,7 @@ pav_x, pav = mycube.get_pav(axis="z", interpolate=True)
 
 ## Macro Averaging
 The `get_mav()` method allows you to compute macro average data with or without interpolation.
-The method `get_mav()` is usually used for determining the electrostatic potential difference across two materials.cite`{Junquera.Rabe.2007.10.1088/0953-8984/19/21/213203}` Assume you have an atomic model of a heterojunction with SiO2 and Si with the interface normal to the `z` axis.  You can specify the length of the first and second periodicity (l1 and l2) for SiO2 and Si. The periodicity can be determined from their interlayer distances normal to the `z` axis. In practice, it is recommended to set periodicity to double minimum interlayer distances to obtain better plateau in the bulk regions of the materials. The `ncov` means the types of systems. `ncov=1` indicates one material with vacuum. In this case, `l2` can be None. `ncov=2` indicates two materials in the box, for example, the SiO2 and Si heterojunction. `l1` and `l2` are set to the periodicity of the two materials, respectively.
+The method `get_mav()` is usually used for determining the electrostatic potential difference across two materials.{cite}`Junquera.Rabe.2007.10.1088/0953-8984/19/21/213203` Assume you have an atomic model of a heterojunction with SiO2 and Si with the interface normal to the `z` axis.  You can specify the length of the first and second periodicity (l1 and l2) for SiO2 and Si. The periodicity can be determined from their interlayer distances normal to the `z` axis. In practice, it is recommended to set periodicity to double minimum interlayer distances to obtain better plateau in the bulk regions of the materials. The `ncov` means the types of systems. `ncov=1` indicates one material with vacuum. In this case, `l2` can be None. `ncov=2` indicates two materials in the box, for example, the SiO2 and Si heterojunction. `l1` and `l2` are set to the periodicity of the two materials, respectively.
 
 ```python
 # Get macro average data without interpolation