core: no visible global function definition for 'cov'
lad: no visible global function definition for 'cov'
lad : InitialMatrix: no visible global function definition for 'cov'
pfc : onepfc: no visible global function definition for 'as.formula'
pfc : onepfc: no visible global function definition for 'lm'
pfc: no visible global function definition for 'cov'
pfc : aniso: no visible global function definition for 'cov'
plot.lad: no visible global function definition for 'plot'
plot.lad: no visible global function definition for 'lines'
plot.lad: no visible global function definition for 'lowess'
plot.lad: no visible global function definition for 'title'
plot.lad: no visible global function definition for 'par'
plot.lad: no visible global function definition for 'legend'
plot.pfc: no visible global function definition for 'plot'
plot.pfc: no visible global function definition for 'lines'
plot.pfc: no visible global function definition for 'lowess'
plot.pfc: no visible global function definition for 'title'
plot.pfc: no visible global function definition for 'par'
plot.pfc: no visible global function definition for 'legend'
screen.pfc : unipfc: no visible global function definition for
  'as.formula'
screen.pfc : unipfc: no visible global function definition for 'lm'
screen.pfc : unipfc: no visible global function definition for 'pf'
structure.test: no visible global function definition for 'pchisq'
summary.core : lrtest: no visible global function definition for
  'pchisq'
summary.lad : lrtest: no visible global function definition for
  'pchisq'
summary.pfc : lrtest: no visible global function definition for
  'pchisq'
summary.pfc : r2: no visible global function definition for 'lm'
Undefined global functions or variables:
  as.formula cov legend lines lm lowess par pchisq pf plot title
Consider adding
  importFrom("graphics", "legend", "lines", "par", "plot", "title")
  importFrom("stats", "as.formula", "cov", "lm", "lowess", "pchisq",
             "pf")
to your NAMESPACE file.